Disposable absorbent article having article retention zones

ABSTRACT

A disposable absorbent garment having an elastic waist panel that includes one or more localized retention zones for retention the garment in its initial, as-applied position on the body of a wearer. The retention zones includes materials that have a higher coefficient of static friction than does the major surface area that constitutes the inner, body-facing surface of the garment. The garment can also include localized areas having a lower coefficient of static friction than that of the major inner surface area of the garment to facilitate placement of the garment in a desired wearing position. Such lower coefficient of static friction areas can include the areas adjacent the leg openings and the area of the waistband that overlies the stomach of the wearer. Additionally, the garment can also include within the waistband, as well as within the side, hip engaging panels of the garment, areas wherein the coefficient of static friction varies from high to low to provide improved retention and comfort over a wide range of wearing conditions and a wide range of movements of the wearer.

FIELD

The present invention relates to disposable absorbent articles, such asincontinence garments for infants, children, and adults, includingdisposable underwear, disposable diapers, disposable pull-on diapers,disposable training pants, and disposable panties for menstrual use.More specifically, the present invention relates to disposable absorbentarticles that include retention zones for preventing slippage of theabsorbent article relative to the body of a wearer during the time thearticle is worn.

BACKGROUND

Infants and others who are incontinent wear disposable absorbentarticles such as diapers or other absorbent undergarments to receive andcontain urine and other bodily exudates. Absorbent articles in the formof garments that are pre-assembled for slip-on application on the bodyof a wearer (e.g., training pants or pull-on diapers) have recentlybecome popular. In order both to contain bodily exudates and also to fita wide variety of body shapes and sizes, such garments must fit snuglyabout the waist and legs of the wearer without drooping, sagging, orsliding down from their position on the lower torso, and without causingunnecessary pressure on the skin by reason of the product being tootight for the wearer's comfort.

Many types of pull-on garments use conventional elastic elements securedin an elastically contractible condition in the waist and leg openings.For example, pull-on absorbent garments known as “balloon type” pantsinclude elasticized bands in specific zones of the product that are incontracted form, while the remaining material tends to blouse. Examplesof such pull-on garments are disclosed in U.S. Pat. No. 5,171,239published on Dec. 15, 1992, U.S. Pat. No. 4,610,681 published on Sep. 9,1986. Those garments will fit a range of waist and leg sizes because theelastic portions will expand to accommodate various size wearers.Nonetheless, the range of sizes is limited because the elastic elements,which enable this variation in size, have a limited degree of stretch.The narrow elastic bands used in the waist opening and the leg openingsalso tend to concentrate the fit forces in a narrow zone of the wearer'sbody leading to increased incidence of skin marking of the wearer.

Other types of pull-on, absorbent garments that employ waist elasticsand side elastics are disclosed in U.S. Pat. No. 4,940,464, published onJul. 10, 1990, U.S. Pat. No. 5,246,433, published on Sep. 21, 1993, U.S.Pat. No. 5,591,155, published on Jan. 7, 1997, EP publication 0 526 868A1 published on Feb. 10, 1993, U.S. Pat. No. 5,545,158 published on Aug.13, 1996; and EP publication 0 547 497 A2, published on Jun. 23, 1993.

Disposable, absorbent garments of the type identified above aregenerally held in position on the body of the wearer by an elasticizedstructure that is positioned in the waist area of the garment. Theelasticized structure is preferably under tension to generate a hoopstress within the waist structure and cause it to engage with and topress against the waist area of the wearer. And to minimize downwardslippage or drooping of such garments while they are worm, the hoopstress within the elasticized waist structure must be large enough tocause an inward force of sufficient magnitude to press against the skinat the wearer's waist. The inward force should be great enough toprovide a normal force against the wearer's body to result in sufficientfriction between the wearer's skin and the inner surface of the elasticwaist structure to overcome those forces that act to tend to pull thegarment down from the wearer's waist, away from garment's initialposition when it was first applied to the wearer. In that regard, thedownward forces acting on the garment to pull it down are caused, inpart, by movements by the wearer, and they are also caused, in part, byan increase in the weight of the absorbent, exudate-receiving core,which results from the absorption and containment by the absorbent coreof waste products in the form of urine and fecal material.

But in providing sufficient hoop stress within the elasticized waiststructure to attempt to cause the garment to be retained in its initialposition on the wearer's body, the inward force acting against thewearer's waist causes pressure and tightness to be exerted on the bodyof the wearer, which can cause wearer discomfort, and can also causeundesirable pressure marks, sometimes referred to as “red marks,” on thewearer's skin about the wearer's waist. Such red marks are indicative ofthe relatively high inward forces that are imposed on the wearers waist,and they are undesirable both because they cause discomfort to thewearer and also because they cause anxiety to mothers of small childrenwho wear such garments. The present invention is directed to minimizingsuch discomfort and the attendant red marking of the wearer's skin byproviding increased surface static friction between the garment and thewearer's skin, which enables the hoop stress, and the resulting inwardforces acting against the wearer's body, to be reduced. Additionally,because it enables lower pressure forces against the skin of a wearer,the present invention also serves to reduce skin abrasion resulting fromrelative movement of portions of such garments and the wearer's skin.

The broad notion of increasing the coefficient of friction of aninterior surface of a disposable diaper is disclosed in U.S. Pat. No.No. 5,782,819, entitled “Article with Stay-In-Place Feature,” whichissued on Jul. 21, 1998, to Tanzer et al., and in Intemational PatentPublication No. WO 95/22306, entitled “Absorbent Pant Diaper,” which waspublished on Aug. 24, 1995, in the name of Kling et al. as inventors.However, the latter does not disclose particular values of coefficientof friction, and it teaches placement of a friction agent at the hipportions of the diaper, but not over the side seams and not in the backportions of the diaper. And the former discloses an arrangement whereinthe dynamic coefficient of friction has a first value when movementoccurs in a first direction, and a second value when movement occurs inthe opposite direction.

It is an object of the present invention to provide a disposableabsorbent article that includes a relatively high coefficient of staticfriction at selected portions of the skin-facing surfaces of thearticle, to retain the article in its desired wearing position duringmovements by the wearer.

It is another object of the present invention to provide a disposableabsorbent article that includes a relatively low coefficient of staticfriction on selected portions of the structure to facilitate applicationof the article to the body of a wearer and also to facilitate removaltherefrom.

SUMMARY

Briefly stated, in accordance with one aspect of the present invention,a disposable garment is provided that has a chassis that includes atopsheet, a backsheet joined with the topsheet, and an absorbent coreinterposed between the topsheet and the backsheet. The chassis has afront region, a back region, a crotch region between the front regionand the back region, and side edges and end edges. A pair of side seamsjoin portions of the side edges of the chassis at the front region toother portions of the respective side edges of the chassis at the backregion to form a garment having pair of laterally spaced leg openingsand a waist opening spaced from each of the leg openings. At least oneretention zone is positioned interiorly of the garment at the waistopening and overlying a side seam. The retention zone has a coefficientof static friction that is at least about 200% greater than that ofother body-contacting portions of the waistband, to assist in retentionof the garment in a desired wearing position on the body of a wearer.

In accordance with another aspect of the present invention, thedisposable garment includes slip zones within the interior, body-facingsurface of the garment to facilitate application and removal of thegarment from the body of a wearer. The slip zones have a relatively lowcoefficient of static friction, of the order of less than about 0.20.The slip zones can be positioned on the inner surface of the waistbandat points between the retention zones, or on the portion of thewaistband that overlies the wearer's stomach when the garment is worn,or they can be positioned around the interior surface adjacent the legopenings to reduce drag during application and removal of the garment.Moreover, zones of intermediate coefficient of static friction, withinthe range of from about 0.20 to about 1.5, can be positioned between theretention zones and the slip zones.

In accordance with a further aspect of the present invention, the innersurface of the waistband can include one or more pivotable flaps. In oneposition of the flaps an area of relatively high coefficient of staticfriction is covered and in a second, pivoted position of the flaps thehigh coefficient of static friction area is exposed to the skin of thewearer. The flap material that pivots about a pivot axis that issubstantially parallel with the circumference of the waistband to exposean area having a coefficient of static friction of the order of fromabout 0.20 to about 1.5.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of a disposable, absorbent, pull-ongarment in accordance with the present invention in assembled form andready for use.

FIG. 2 is a plan view of the disposable garment of FIG. 1 in its flat,uncontracted, and unseamed condition and showing various panels andedges that define the several portions of the garment.

FIG. 3 is a plan view of the garment shown in FIG. 1 when it is in itsflat, uncontracted, and unseamed condition and showing the relativepositions of the several structural components of the garment.

FIG. 4 is a cross-sectional view taken along the line 4—4 of FIG. 3.

FIG. 5 is a cross-sectional view taken along the line 5—5 of FIG. 3.

FIG. 6 is an enlarged, fragmentary perspective view in exploded formshowing the structure of an elastic component of the garment.

FIG. 7 is a graph of force plotted against percent extension for thecontinuous belt zone of a garment in accordance with the presentinvention.

FIG. 8 is a graph of modulus of extensibility plotted against percentextension corresponding with the data shown in FIG. 7.

FIG. 9 is a perspective view of a standard mannequin used to measureskin contact pressure.

FIG. 10 is a side view of the standard mannequin shown in FIG. 9.

FIG. 11 is a top view of the standard mannequin shown in FIG. 9.

FIG. 12 is an enlarged, fragmentary view into the interior of thegarment shown in FIG. 1, at the waist area, showing an inner flapmember.

FIG. 13 is cross-sectional view taken along the line 13—13 of FIG. 12.

FIG. 14 is a fragmentary perspective view of the waist area of thegarment of FIG. 1 including several inner flap members.

FIG. 15 is an exploded perspective view of materials and apparatus formaking a high coefficient of static friction composite.

FIG. 16 is a side view of the materials and apparatus of FIG. 15 inposition for commencement of a joining operation.

FIG. 17 is a side view of the materials and apparatus of FIG. 15 duringthe execution of a joining operation.

FIG. 18 is a side view of the materials and apparatus of FIG. 15 afterthe materials have been joined.

FIG. 19 is a top view of the waistband area of the article shown in FIG.1 wherein the article includes waistband zones of increased staticcoefficient for friction.

FIG. 20 is a perspective view of an absorbent, pull-on diaperincorporating waistband-positioned retention zones.

FIG. 21 is a fragmentary perspective view of the interior waistband areaof an absorbent, pull-on diaper that incorporates pivotable inner flaps.

FIG. 22 is a cross-sectional view taken along the line 22—22 of FIG. 21showing a unitary pivotable flap.

FIG. 22a is a view similar to that of FIG. 22, but showing a pluralityof shorter, parallel flaps

FIG. 23 is a fragmentary perspective view of a porous, elastomeric web.

FIG. 23a is a fragmentary plan view of an inner, body-facing layer ofwaistband material that includes a plurality of spaced slits or cuts.

FIG. 23b is a fragmentary plan view of the material shown in FIG. 23aafter it has been subjected to a tensile force.

FIG. 24 is perspective view of another embodiment of a pull-on diaper inaccordance with the present invention.

FIG. 25 is a perspective view of a still further embodiment of a pull-ondiaper in accordance with the present invention.

DETAILED DESCRIPTION

As used herein, “pull-on garment” refers to articles of wear which havea defined waist opening and a pair of leg openings and which are pulledonto the body of the wearer by inserting the legs into the leg openingsand pulling the article up over the waist.

As used herein, “disposable” describes garments which are not intendedto be laundered or otherwise restored or reused as a garment (i.e., theyare intended to be discarded after a single use and, preferably, to berecycled, composted or otherwise disposed of in an environmentallycompatible manner).

As used herein, a “unitary” pull-on garment refers to pull-on garmentswhich are formed of separate parts united together to form a coordinatedentity, but the ear panels are not separate elements joined to aseparate chassis in that the ear panels are formed by at least one layerwhich also forms the central panel or chassis of the garment (i.e., thegarment does not require separately manipulative panels such as aseparate chassis and separate ear panels). The pull-on garment is alsopreferably “absorbent” to absorb and contain the various exudatesdischarged from the body. A preferred embodiment of the pull-on garmentof the present invention is the unitary disposable absorbent pull-ongarment, pull-on diaper 20, shown in FIG. 1.

As used herein, “pull-on diaper” refers to pull-on garments generallyworn by infants and other incontinent individuals to absorb and containurine and feces. It should be understood, however, that the presentinvention is also applicable to other pull-on garments such as trainingpants, incontinent briefs, feminine hygiene garments or panties, and thelike.

As used herein, “joined” or “joining” encompasses configurations wherebyan element is directly secured to the other element by affixing theelement directly to another element, and configurations whereby theelement is indirectly secured to the other element by affixing theelement to intermediate member(s) which in turn are affixed to the otherelement.

As used herein, “longitudinal” refers to a line, axis, or direction inthe plane of a pull-on diaper that is generally aligned with (e.g.approximately parallel with) a vertical plane which bisects a standingwearer into left and right halves when the pull-on diaper is worn.

As used herein, “transverse” and “lateral” are interchangeable and referto a line, axis, or direction that lies within the plane of the diaperthat is generally perpendicular to the longitudinal direction (whichdivides the wearer into front and back body halves).

Referring to FIGS. 1, 2, and 3, pull-on diaper 20 has a front region 26,a back region 28, and a crotch region 30 that is positioned betweenfront region 26 and back region 28. Diaper 20 also has two centerlines,a longitudinal centerline 100, and a transverse centerline 110, and thecomponent materials thereof have a body-facing surface which faces theskin of wearer in use and an outer-facing surface that faces away fromthe body-facing surface.

FIG. 2 is a plan view of the pull-on diaper 20 of FIG. 1 in itsflat-out, uncontracted state showing the various panels that togetherdefine the diaper structure and their positions relative to each other.The term “panel” is used herein to denote an area or an element of thepull-on diaper or the belt. Although a panel is typically a distinctarea or element, a panel can coincide or functionally correspond with anadjacent panel.

A shown in FIG. 2, diaper 20 has a crotch region 30 that includes a mainpanel 2 and a pair of elongated, generally rectangular leg flap panels 4that are connected with main panel 2 along respective longitudinal edges2B. A front region 26 comprising a central panel (medial panel) 8, awaistband panel 6, ear panels 10, and seam panels 12; and a back region28 comprising a central panel (medial panel) 9, a waistband panel 7, earpanels 11, and seam panels 13. The crotch region 30 is the portion ofthe pull-on diaper 20 from which the continuous belt (the other panels)emanates. The absorbent core is generally positioned within the mainpanel 2 since exudates are typically discharged in this region althoughthe absorbent core will typically extend into the medial panels 8 and 9of the belt. A leg flap panel 4 extends generally laterally outwardlyfrom and along each side edge 2B of the main panel 2. Each leg flappanel 4 generally forms at least a portion of the elastic leg feature.

The continuous belt zone (the front region 26 and the back region 28)extends generally longitudinally outwardly from and along each lateraledge 159 of the crotch region 30 (the main panel 2 and the leg flappanel 4). In the front region 26, the medial panel 8 (i.e., centralpanel) extends generally longitudinally outwardly from and along thelateral edge 159 of the crotch region 30. The medial panel 8 has a waistedge 190 and side edges 191.

The ear panels 10 each extend generally laterally outwardly from andalong the side edge 191 of the medial panel 8 (i.e., central panel). Theear panel 10 has a waist edge 161 and a side edge 171. The waistbandpanel 6 extends generally longitudinally outwardly from and along thewaist edge 190 of the medial pajel 8 (i.e., central panel) and the waistedge 161 of the ear panel 10. The waistband panel 6 has side edges 175.

The seam panels 12 each extend generally laterally outwardly from andalong the side edge 171 of the ear panel 10 and the side edge 175 of thewaistband panel 6. In the back region 28, the medial panel 9 (i.e.,central panel) extends generally longitudinally outwardly from and alongthe other lateral edge 159 of the crotch region 30.

The medial panel 9 has a waist edge 192 and side edges 193. The earpanels 11 each extend generally laterally outwardly from and along theside edge 193 of the medial panel 9 (i.e., central panel). The ear panel11 has a waist edge 163 and a side edge 173.

The waistband panel 7 extends generally longitudinally outwardly fromand along the waist edge 192 of the medial panel 9 (i.e., central panel)and the waist edge 163 of the ear panel 11. The waistband panel 7 hasside edges 177. The seam panels 13 each extend generally laterallyoutwardly from and along the side edge 173 of the ear panel 11 and theside edge 177 of the waistband panel 7. The front region 26, in additionto its panels, also has a waist edge 151, leg edges 153, and side edges154. The back region 28, in addition to its panels, also has a waistedge 155, leg edges 156, and side edges 157. The crotch region 30 hasleg edges 158.

Diaper 20 includes a chassis 41, a waist elastomeric material (not shownin FIGS. 1, 2, and 3), a side elastomeric material (not shown in FIGS.1, 2, and 3), and seams 32. The pull-on diaper 20 can have tear opentabs 31, whose positioning is associated with the seams 32 andelasticized leg cuffs 52 including inner barrier cuffs 54. The sideelastomeric material renders at least a part of the ear panel 10 and 11extensible, thereby forming extensible ear 46 and 48. The waistelastomeric material renders at least a part of the waistband panel 6and 7 extensible, thereby forming continuous extensible waistband 57 and59. The side elastomeric material and the waist elastomeric material areseparate elements to each other and disposed so as not to overlap toeach other in the longitudinal direction of the pull-on diaper 20. Thisallows more independent behavior of the waist and side elastomericmaterials to allow for adjustments in dimension extension, pressure,etc. The extensible ear 46 and 48 and continuous extensible waistband 57and 59 are extensible at least in the lateral direction. The seam 32joins the seam panel 12 in the front region 26 to the seam panel 13 inthe back region 28, whereby the ear panel 10 is joined to the ear panel11 and whereby one waist opening 36 and two leg openings 34 are formed.In the configuration where the ear panel 10 is joined to the ear panel11, the continuous extensible waistband 57 and 59 forms a continuousextensible waist feature 60 about the waist opening 36. Further, acontinuous belt zone 38 extends in the front region 26 and the backregion 28.

Referring to FIG. 3, the chassis 41 comprises an absorbent core 25 and aplurality of layers disposed in association with the absorbent core 25,such as a topsheet 24 and a backsheet 22 associated with the topsheet24. The absorbent core 25 is disposed between the topsheet 24 and thebacksheet 22. The chassis 41 further can include one or more additionallayers disposed associated with the absorbent core 25. The topsheet 24has the body-facing surface that is positioned adjacent to the wearer'sbody during use. The backsheet 22 has the outer-facing surface that ispositioned away from the wearer's body. Preferably, the backsheet 22comprises an inner barrier film 68 and a nonwoven outer cover 23. Sincethe chassis 41 defines the front region 26, the back region 28, andcrotch region 30, the chassis 41 also has corresponding regions andpanels as previously defined. (For simplicity, these regions and panelsare denoted in the drawings by the same reference numerals as thecorresponding pull-on diaper regions and panels as shown in FIG. 2.)

The topsheet 24 and the inner barrier film 68 of the backsheet 22 havelength and width dimensions generally larger than those of the absorbentcore 25. The topsheet 24 and the inner barrier film 68 extend beyond theside edges and end edges of the absorbent core 25 to thereby form theperiphery of the chassis 41. The topsheet 24 longitudinally extendsbetween the waist edge 151 and 155 of the pull-on diaper 20. Thetopsheet 24 has waist end portions 24A and side portions 24B. The waistend portions 24A (i.e., end extended portion 24A) of the topsheet 24extend into a portion of the waistband panel 6 and 7 of the pull-ondiaper 20. The inner barrier film 68 has waist end portions 68A and sideportions 68B. The inner barrier film 68 is a little shorter in thelongitudinal direction than the topsheet 24 and a little wider in thelateral direction than the topsheet 24. The inner barrier film 68 has anonuniform lateral width so as to form a first portion 94 in at least aportion of the crotch region 30 and a second portion 96 in at least aportion of the front or back region 26 and 28. The lateral width of theinner barrier film 68 gradually decreases towards the waist end portions68A such that the second portion 96 has a lateral width dimension lessthan the lateral width dimension of the first portion 94. The innerbarrier film 68 does not preferably extend into the ear panel 10 and 11so as to increase the effective lateral extended length of the ear panel10 and 11 and reduce bulkiness of the ear panel 10 and 11. The innerbarrier film 68 also does not extend into the waistband panel 6 and 7 soas to reduce bulkiness of the waistband panel 6 and 7. In addition,since the inner barrier film 68 does not extend into both the ear panels10 and 11 and the waistband panel 6 and 7, the inner barrier film 68does not inhibit breathability in those areas. While the topsheet 24,the inner barrier film 68, and the absorbent core 25 can be assembled ina variety of well known configurations, exemplary chassis configurationsare described generally in U.S. Pat. No. No. 3,860,003, entitled“Contractible Side Portions for Disposable Diaper,” which issued toKenneth B. Buell on Jan. 14, 1975; and in U.S. Pat. No. 5,151,092,entitled “Absorbent Article With Dynamic Elastic Waist Feature Having APredisposed Resilient Flexural Hinge,” which issued to Kenneth B. Buellet al., on Sep. 29, 1992.

Preferably, the nonwoven outer cover 23 covers almost all of the area ofthe outermost portion of the pull-on diaper 20. The nonwoven outer cover23 can have generally the same shape as the pull-on diaper 20. Thenonwoven outer cover 23 has waist end portions 23A and side portions23B. The nonwoven outer cover 23 also has a side extended portion 23C inthe front region 26 and a side extended portion 23D in the back region28. The waist end portion 23A (i.e., end extended portion 23A) of thenonwoven outer cover 23 extends into the waistband panel 6 and 7, andthe side extended portion 23C and 23D of the nonwoven outer cover 23extends into the ear panel 10 and 11. Alternatively, the nonwoven outercover 23 of the backsheet 22 can have generally same shape as the innerbarrier film 68 such that the nonwoven outer cover 23 covers only thearea of the inner barrier film 68. Alternatively, the nonwoven outercover 23 can be eliminated, and the inner barrier film 68 can havegenerally the same shape as the pull-on diaper 20 and extend into bothear panel 10 and 11 and waistband panel 6 and 7.

The absorbent core 25 can be any absorbent member that is generallycompressible, conformable, non-irritating to the wearer's skin, andcapable of absorbing and retention liquids such as urine and othercertain body exudates. The absorbent core 25 can be manufactured in awide variety of sizes and shapes (e.g., rectangular, hourglass,“T”-shaped, asymmetric, etc.) and from a wide variety of liquidabsorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding; meltblown polymers including coform;chemically stiffened, modified or cross-linked cellulosic fibers; tissueincluding tissue wraps and tissue laminates; absorbent foams; absorbentsponges; superabsorbent polymers; absorbent gelling materials; or anyequivalent material or combinations of materials.

The configuration and construction of the absorbent core 25 can vary(e.g., the absorbent core 25 can have varying caliper zones, ahydrophilic gradient, a superabsorbent gradient, or lower averagedensity and lower average basis weight acquisition zones; or cancomprise one or more layers or structures). Further, the size andabsorbent capacity of the absorbent core 25 can also be varied toaccommodate wearers ranging from infants through adults. However, thetotal absorbent capacity of the absorbent core 25 should be compatiblewith the design loading and the intended use of the diaper 20.

The absorbent core 25 in a preferred embodiment has an asymmetric,modified hourglass-shape having ears in the front and back waist regions26 and 28. Other exemplary absorbent structures for use as the absorbentcore 25 that have achieved wide acceptance and commercial success aredescribed in U.S. Pat. No. No. 4,610,678, entitled “High-DensityAbsorbent Structures,” which issued to Weisman et al. on Sep. 9, 1986;in U.S. Pat. No. No. 4,673,402, entitled “Absorbent Articles WithDual-Layered Cores,” which issued to Weisman et al. on Jun. 16, 1987; inU.S. Pat. No. 4,888,231, entitled “Absorbent Core Having A DustingLayer,” which issued to Angstadt on Dec. 19, 1989; and in U.S. Pat. No.4,834,735, entitled “High Density Absorbent Members Having Lower Densityand Lower Basis Weight Acquisition Zones,” which issued to Alemany etal. on Can 30, 1989.

The chassis 41, as shown in FIG. 4, can further include anacquisition/distribution core 84 of chemically stiffened fiberspositioned over the absorbent core 25, thereby forming a dual coresystem. Preferred dual core systems are disclosed in U.S. Pat. No.5,234,423, entitled “Absorbent Article With Elastic Waist Feature andEnhanced Absorbency,” which issued to Alemany et al., on Aug. 10, 1993;and in U.S. Pat. No. 5,147,345, entitled “High Efficiency AbsorbentArticles For Incontinence Management,” which issued to Young et al. onSep. 15, 1992. In a preferred embodiment, the acquisition/distributioncore 84 comprise chemically treated stiffened cellulosic fiber material,available from Weyerhaeuser Co. (U.S.A.) under the trade designation ofCMC.

Alternatively, the chassis 41 can further include anacquisition/distribution layer 82 between the topsheet 24 and theacquisition/distribution core 84 as shown in FIG. 4. Theacquisition/distribution layer 82 is provided to help reduce thetendency for surface wetness of the topsheet 24. Theacquisition/distribution layer 82 preferably comprises carded, resinbonded hiloft nonwoven materials such as, for example, available as CodeNo. FT-6860 from Polymer Group, Inc., North America (Landisiville, N.J.,U.S.A.), which is made of polyethylene terephthalate fibers of 6 dtex,and has a basis weight of about 43 g/m².

The topsheet 24 is preferably compliant, soft feeling, andnon-irritating to the wearer's skin. Further, the topsheet 24 is liquidpervious permitting liquids (e.g., urine) to readily penetrate throughits thickness. A suitable topsheet 24 can be manufactured from a widerange of materials such as woven and nonwoven materials; polymericmaterials such as apertured formed thermoplastic films, aperturedplastic films, and hydroformed thermoplastic films; porous foams;reticulated foams; reticulated thermoplastic films; and thermoplasticscrims. Suitable woven and nonwoven materials can be comprised ofnatural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g.,polymeric fibers such as polyester, polypropylene, or polyethylenefibers) or from a combination of natural and synthetic fibers.

The topsheet 24 is preferably made from a hydrophobic material toisolate the wearers skin from liquids which have passed through thetopsheet 24 and are contained in the absorbent core 25 (i.e., to preventrewet). If the topsheet 24 is made of a hydrophobic material, it ispreferable that at least the upper surface of the topsheet 24 is treatedto be hydrophilic so that liquids will transfer through the topsheetmore rapidly. This diminishes the likelihood that body exudates willflow off the topsheet 24 rather than flowing through the topsheet 24 andto the absorbent core 25. The topsheet 24 can be rendered hydrophilic bytreating it with a surfactant. Suitable methods for treating thetopsheet 24 with a surfactant include spraying the topsheet 24 materialwith the surfactant and immersing the material into the surfactant. Amore detailed discussion of such a treatment and hydrophilicity iscontained in U.S. Pat. No. 4,988,344, entitled “Absorbent Articles withMultiple Layer Absorbent Layers,” which issued to Reising, et al on Jan.29, 1991; and in U.S. Pat. No. 4,988,345, entitled “Absorbent Articleswith Rapid Acquiring Absorbent Cores,” which issued to Reising on Jan.29, 1991. The topsheet 24 can be compatible with ventilationdesign/process preferably along the waistband panel 6 and 7 and otherportions on the pull-on diaper 20.

In preferred embodiments, the topsheet 24 is a nonwoven web that canprovide reduced tendency for surface wetness; and consequentlyfacilitate maintaining urine absorbed by the absorbent core 25 away fromthe user's skin, after wetting. One of the preferred topsheet materialsis a thermobonded, carded web that is available as Code No. P-8 fromFiberweb North America, Inc. (Simpsonville, S.C., U.S.A.). Anotherpreferred topsheet material is available as Code No. S-2355 from HavixCo., Japan. This material is a bi-layer composite material, and made oftwo kinds of synthetic surfactant treated bicomponent fibers by usingcarding and air-through technologies. Yet another preferred topsheetmaterial is a thermobonded, carded web that is available as Code No.Profleece Style 040018007 from Amoco Fabrics, Inc. (Gronau, Germany).

Another preferred topsheet 24 comprises an apertured formed film.Apertured formed films are preferred for the topsheet 24 because theyare pervious to body exudates and yet non-absorbent and have a reducedtendency to allow liquids to pass back through and rewet the wearer'sskin. Thus, the surface of the formed film that is in contact with thebody remains dry, thereby reducing body soiling, and creating a morecomfortable feel for the wearer. Suitable formed films are described inU.S. Pat. No. 3,929,135, entitled “Absorptive Structures Having TaperedCapillaries,” which issued to Thompson on Dec. 30, 1975; in U.S. Pat.No. 4,324,246, entitled “Disposable Absorbent Article Having A StainResistant Topsheet,” which issued to Mullane, et al. on Apr. 13, 1982;in U.S. Pat. No. 4,342,314, entitled “Resilient Plastic Web ExhibitingFiber-Like Properties,” which issued to Radel et al. on Aug. 3, 1982; inU.S. Pat. No. 4,463,045, entitled “Macroscopically ExpandedThree-Dimensional Plastic Web Exhibiting Non-Glossy Visible Surface andCloth-Like Tactile Impression,” which issued to Ahr et al. on Jul. 31,1984; and in U.S. Pat. No. 5,006,394, entitled “Multilayer PolymericFilm,” which issued to Baird on Apr. 9, 1991.

The backsheet 22 preferably comprises an inner barrier film 68 and anonwoven outer cover 23. The inner barrier film 68 is preferablyimpervious to liquids (e.g., urine) and is preferably manufactured froma thin plastic film. The inner barrier film 68 has a body-facing surface79 and an outer-facing surface 77. More preferably the plastic filmpermits vapors to escape from the diaper 20. In a preferred embodiment,a microporous polyethylene film is used for the inner barrier film 68. Asuitable microporous polyethylene film is manufactured by Mitsui ToatsuChemicals, Inc., Nagoya, Japan and marketed in the trade as Espoir No.The backsheet 22 is preferably compatible with ventilation and sideseaming design/process. A disposable tape can be further joined to theouter surface of the backsheet.

A suitable plastic film material for the inner barrier film 68 is athermoplastic film having a thickness of from about 0.012 mm (0.5 mil)to about 0.051 mm (2.0 mils), preferably comprising polyethylene orpolypropylene. Preferably, the plastic film has a basis weight of fromabout 5 g/m² to about 35 g/m². However, it should be noted that otherflexible, liquid impervious materials can be used. Herein “flexible”refers to materials which are compliant and which will readily conformto the general shape and contours of the wearer's body. The plastic filmcan have moisture vapor transmission rate of between 3,000 and 4,000g/m²/24 hr, which is measured by a method set forth below.

The nonwoven outer cover 23 is joined with the outer-facing surface ofthe inner barrier film 68 to form a laminate (i.e., the backsheet 22).The nonwoven outer cover 23 is positioned at the outermost portion ofthe pull-on diaper 20 and covers at least a portion of the outermostportion of the diaper 20. The nonwoven outer cover 23 can be joined tothe inner barrier film 68 by any suitable attachment means known in theart. For example, the nonwoven outer cover 23 can be secured to theinner barrier film 68 by a uniform continuous layer of adhesive, apatterned layer of adhesive, or an array of separate lines, spirals, orspots of adhesive. Suitable adhesives include a hotmelt adhesiveobtainable from Nitta Findley Co., Ltd., Osaka, Japan as H-2128, and ahotmelt adhesive obtainable from H. B. Fuller Japan Co., Ltd., Osaka,Japan as JM-6064.

In a preferred embodiment, the nonwoven outer cover 23 is a cardednonwoven web, for example, obtainable from Havix Co., LTD., Gifu, Japanas E-2341. The nonwoven outer cover 23 is made of bi-component fibers ofa polyethylene (PE) and a polyethylene terephthalate (PET). The ratio ofPE/PET is about 40/60. The PE/PET bi-component fiber has the dimensionof 2 decitex×51 mm. Another preferred carded nonwoven web is obtainablefrom Chisso Corp., Osaka, Japan. The nonwoven outer cover 23 is alsomade of bi-component fibers of a polyethylene (PE) and a polyethyleneterephthalate (PET). The ratio of PE/PET is about 30/70.

In another preferred embodiment, the nonwoven web is a spunbondednonwoven web, for example, obtainable from Mitsui PetrochemicalIndustries, Ltd., Tokyo, Japan. The nonwoven web is made of bi-componentfibers consisting of a polyethylene (PE) sheath and a polypropylene (PP)core. The ratio of PE/PP is about 80/20. The PE/PP bi-component fiberhas the thickness of approximately 2.3 decitex.

The backsheet 22 is preferably positioned adjacent the outer-facingsurface of the absorbent core 25 and is preferably joined thereto by anysuitable attachment means known in the art. For example, the backsheet22 can be secured to the absorbent core 25 by a uniform continuous layerof adhesive, a patterned layer of adhesive, or an array of separatelines, spirals, or spots of adhesive. Adhesives that have been found tobe satisfactory are manufactured by H. B. Fuller Company of St. Paul,Minn. and marketed as HL-1258. An example of a suitable attachment meanscomprising an open pattern network of filaments of adhesive is disclosedin U.S. Pat. No. 4,573,986 entitled “Disposable Waste-ContainmentGarment”, which issued to Minetola et al. on Mar. 4, 1986. Anothersuitable attachment means comprising several lines of adhesive filamentsswirled into a spiral pattern is illustrated by the apparatus andmethods shown in U.S. Pat. No. 3,911,173, which issued to Sprague, Jr.on Oct. 7, 1975; in U.S. Pat. No. 4,785,996, which issued to Ziecker, etal. on Nov. 22, 1978; and U.S. Pat. No. 4,842,666, which issued toWerenicz on Jun. 27, 1989. Alternatively, the attachment means cancomprise heat bonds, pressure bonds, ultrasonic bonds, dynamicmechanical bonds, or any other suitable attachment means or combinationsof these attachment means as are known in the art.

In an alternative embodiment, the absorbent core 25 is not joined to thebacksheet 22, and/or the topsheet 24 in order to provide greaterextensibility in the front region 26 and the back region 28.

The elasticized leg cuffs 52 provides improved containment of liquidsand other body exudates. The elasticized leg cuffs 52 can compriseseveral different embodiments for reducing the leakage of body exudatesin the leg regions. (The leg cuff can be and is sometimes also referredto as leg bands, side flaps, barrier cuffs, or elastic cuffs.) U.S. Pat.No. 3,860,003 describes a disposable diaper which provides acontractible leg opening having a side flap and one or more elasticmembers to provide an elasticized leg cuff (gasketing cuff). U.S. Pat.No. 4,909,803 entitled “Disposable Absorbent Article Having ElasticizedFlaps” issued to Aziz et al. on Mar. 20, 1990, describes a disposablediaper having “stand-up” elasticized flaps (barrier cuffs) to improvethe containment of the leg regions. U.S. Pat. No. 4,695,278 entitled“Absorbent Article Having Dual Cuffs” issued to Lawson on Sep. 22, 1987;and U.S. Pat. No. 4,795,454 entitled “Absorbent Article HavingLeakage-Resistant Dual Cuffs” issued to Dragoo on Jan. 3, 1989, describedisposable diapers having dual cuffs including a gasketing cuff and abarrier cuff. U.S. Pat. No. 4,704,115 entitled “Disposable WaistContainment Garment” issued to Buell on Nov. 3, 1987, discloses adisposable diaper or incontinence garment having side-edge-leakage-guardgutters configured to contain free liquids within the garment.

While each elasticized leg cuff 52 can be configured so as to be similarto any of the leg bands, side flaps, barrier cuffs, or elastic cuffsdescribed above, it is preferred that each elasticized leg cuff 52comprises inner barrier cuffs 54 each comprising a barrier flap 56 and aspacing means 58 (as shown in FIG. 5) as described in theabove-referenced U.S. Pat. No. 4,909,803. The inner barrier cuffs 54 canhave an insert element that is highly impermeable, but preferablybreathable. In a preferred embodiment, the elasticized leg cuff 52additionally comprises an elastic gasketing cuff 62 with one or moreelastic strands 64, positioned outboard of the barrier cuff 54 such asdescribed in the above-referred U.S. Pat. Nos. 4,695,278 and 4,795,454.The elastic strands 64 are generally disposed in the leg flap panel 4and are joined thereto by any means, such as hot melt glue under aprestrained condition. The elastic strands 64 can be prestrained, beforebeing joined, up to between 30% and 200%, preferably between 50% and150%. A preferred elastic strand 64 is manufactured by FulflexInternational Company under the designation 9312.

The pull-on diaper 20 has the front extensible ear 46 and the backextensible ear 48. Referring to FIG. 4, the extensible ear 46 and 48preferably comprises a side elastic member 70 having a side elastomericmaterial 124 (shown in FIG. 6), the side extended portion 23C of thenonwoven outer cover 23, and an extended portion 72 of the inner barriercuff 54 (although FIG. 4 shows only the structures in the front region26, preferably the structures in the back region 28 are the same orsimilar to those in the front region 26). Preferably at least one of thefront and back extensible ears 46 and 48 is elastically extensible in atleast the lateral direction. More preferably, both the front and tieback extensible ears 46 and 48 are elastically extensible in at leastthe lateral direction. In an alternative embodiment, the front and backextensible ear 46 and 48 is elastically extensible both in the lateraland longitudinal directions. Herein “extensible” refers to materialsthat are capable of extending in at least one direction to a certaindegree without undue rupture. Herein “elasticity” and “elasticallyextensible” refer to extensible materials that have the ability toreturn to approximately their original dimensions after the force thatextended the material is removed. Herein any material or elementdescribed as “extensible” can also be elastically extensible unlessotherwise provided. The extensible ear 46 and/or 48 provides a morecomfortable and contouring fit by initially conformably fitting thediaper to the wearer and sustaining this fit throughout the time of wearwell past when the diaper has been loaded with exudates since theextensible ear 46 and/or 48 allows the sides of the diaper to expand andcontract.

The extensible ear 46 and 48 preferably has breathability. The moisturevapor transmission rate of the ear panel in conjunction with the overallvapor transmission rate of the rest of the pull-on diaper is importantin reducing the incidence of heat rash and other skin problemsassociated with high heat humidity conditions. In order to reducehumidity and heat humidity within the pull-on diaper, the extensible ear46 and 48 preferably has a weighed average mass vapor transmission rateof at least about 2,000 g/m²/24 hr, more preferably at least 4,000g/m²/24 hr. Preferably, the entire pull-on diaper has a weighed averagemass vapor transmission rate of from at least 2,000 g/m²/24 hr to about8,000 g/m²/24 hr.

The moisture vapor transmission rate is measured by the method set forthbelow. A known amount of CaCl₂ is put into a flanged cup. A sample isplaced on the top of the cup and held securely by a retention ring andgasket. The assembly is then weighed and recorded as the initial weight.The assembly is placed in a constant temperature (40° C.) and humidity(75% RH) chamber for 5 hours. The assembly is then removed from thechamber and allowed to equilibrate for at least 30 minutes at thetemperature of the room where the balance is located. The assembly isthen weighed and recorded as the final weight. The mass vaportransmission rate (MVTR) is calculated and expressed in g/m²/24 hr usingthe following formula.${MVTR} = \frac{\left( {{{Final}\quad {weight}} - {{initial}\quad {weight}}} \right) \times 24.0}{{Area}\quad {of}\quad {sample}\quad {in}\quad {meters} \times 5.0\quad \left( {{time}\quad {in}\quad {chamber}} \right)}$

Referring to FIG. 3, the extensible ear 46 comprising the side elasticmember 70 has a higher end edge 46A, a lower end edge 46B, an inner sideedge 46C, and an outer side edge 46D. The back extensible ear 48comprising the side elastic material 70 has a higher end edge 48A, alower end edge 48B, an inner side edge 48C, and an outer side edge 48D.Although a configuration of each element, portion, part, etc. in thefront region 26 can be different from that in the back region 28 (suchas configuration of the front extensible ear 46 and configuration of theback extensible ear 48, or configuration of the lower end edge 46B andconfiguration of the lower end edge 48B), those elements, portions,parts, etc. which correspond to each other in the front region 26 and inthe back region 28 can be described concurrently for ease ofdescription.

In a preferred embodiment, the ear panel 10 and 11 is renderedextensible in the entire area of the ear panel 10 and 11 to form theextensible ear 46 and 48 by the side elastic material 70. In theembodiment shown in FIG. 3, the side elastic material 70 extends into apart of the seam panel 12 and 13 so that the front extensible ear 46 andthe back extensible ear 48 are anchored each other at the seam 32, andthe side elastic material 70 in the front region 26 and the side elasticmaterial 70 in the back region 28 are anchored at the seam 32 (FIG. 4also shows the side elastic member 70 which extends into the seam panel12 and 13, though the seam panel 12 and 13 is not shown in FIG. 4).Alternatively, the ear panel 10 and 11 can be rendered extensible onlyin a portion of the area in the ear panel 10 and 11. The extensible ear46 and 48 is the part of the ear panel 10 and 11 rendered extensible byjoining the side elastic member 70 and being subjected to mechanicalstretching.

In a preferred embodiment, the inner side edge 46C and 48C extendsgenerally along the longitudinal centerline 100 of the pull-on diaper20. The outer side edge 46D and 48D is non-parallel to the inner sideedge 46C and 48C and is non-parallel to the longitudinal centerline 100.The outer side edge 46D and 48D projects laterally outwardly proximatethe lower end edge 46B and 48B. Therefore, the outer side edges 46D and48D remote from the inner side edge 46C and 48C proximate the lower endedge 46B and 48B.

The extensible ear 46 and 48 has a lateral width L1 between the innerside edge 46C and 48C and the outer side edge 46D and 48D proximate thelower end edge 46B and 48B, and a lateral width L2 between the innerside edge 46C and 48C and the outer side edge 46D and 48D proximate thehigher end edge 46A and 48A. The lateral width between the inner sideedge and the outer side edge is the width between the inner side edge46C and 48C and the outer side edge 46D and 48D in the lateral directionperpendicular to the longitudinal center line 100. Therefore, thelateral width between the inner side edge and the outer side isavailable in the range R where the inner side edges 46C and 48C and theouter side edge 46D and 48D co-extend in the longitudinal direction.

The lateral width L1 is greater than the lateral width L2, therefore,the available elastomeric material quantity in the lateral direction ofthe extensible ear 46 and 48 is greater proximate the lower end edge 46Band 48B than proximate the higher end edge 46A and 48A. Because theouter side edge 46D and 48D projects laterally outwardly proximate thelower end edge 46B and 48B, available elastomeric material quantityproximate the lower end edge 46B and 48B is enhanced without reducingavailable elastomeric material quantity proximate the higher end edge46A and 48A. Further, the available elastomeric material quantitychanges in the direction from the higher end edge 46A and 48A toward thelower end edge 46B and 48B because the lateral width of the extensibleear 46 and 48 gradually changes in that direction. This results inchange of forces or force gradient over the extensible ear allowing forcustom fit. The inner side edge 46C and 48C also can be non-parallel tothe longitudinal center line 100 and project laterally inwardlyproximate the lower end edge 46B and 48B such that the lateral width L1becomes further greater than the lateral width L2. Alternatively, theinner side edge 46C and 48C can project a little laterally outwardlyproximate the lower end edge 46B and 48B such that the lateral width L1is still greater than the lateral width L2.

The extensible ear 46 and 48 can be formed by unitary elements of thepull-on diaper 20 (i.e., they are not separately manipulative elementssecured to the pull-on diaper 20, but rather are formed from and areextended portions of one or more of the various layers of the pull-ondiaper). In a preferred embodiment, the extensible ear 46 and 48 is aprojected member of the chassis 41. Preferably, the extensible ear 46and 48 comprises at least one unitary element or a continuous sheetmaterial that forms a part of the chassis 41 and continuously extends tothe extensible ear 46 and 48. Alternatively, the extensible ear 46 and48 can be discrete members that do not have any unitary element thatforms a part of the chassis 41. The extensible ear 46 and 48 can beformed by joining the discrete members to the side portions of thechassis 41.

The side elastic member 70 is interposed between the extended portion 72of the inner barrier cuff 54 and the side extended portion 23C and 23Dof the nonwoven outer cover 23 in the region of the extensible ear 46and 48. The side elastic member 70 is operatively joined to at least oneof the extended portion 72 of the inner barrier cuff 54 and the sideextended portion 23C and 23D of the nonwoven outer cover 23. Preferably,the side elastic member 70 is operatively joined to both the extendedportion 72 of the inner barrier cuff 54 and the side extended portion23C and 23D of the nonwoven outer cover 23 while in a substantiallyuntensioned (zero strain) condition.

The side elastic member 70 can be operatively joined to the innerbarrier cuff 54 and the nonwoven outer cover 23, by using either anintermittent bonding configuration or a substantially continuous bondingconfiguration. Herein an “intermittently” bonded laminate web means alaminate web wherein the plies are initially bonded to one another atdiscrete spaced points or a laminate web wherein the plies aresubstantially unbonded to one another at discrete spaced areas.Conversely, a “substantially continuously” bonded laminate web means alaminate web wherein the plies are initially bonded substantiallycontinuously to one another throughout the areas of interface. Becauseit is preferred that the stretch laminate be bonded over all or asignificant portion of the stretch laminate so that the inelastic webs(i.e., nonwoven webs of the inner barrier cuff 54 and the nonwoven outercover 23) elongate or draw without causing rupture, and the layers ofthe stretch laminates are preferably bonded in a configuration thatmaintains all of the layers of the stretch laminate in relatively closeadherence to one another after the incremental mechanical stretchingoperation, the side elastic member and the other plies of the stretchlaminate are substantially continuously bonded together using anadhesive.

In a particularly preferred embodiment, the adhesive selected is appliedin a spiral pattern (such as is shown in U.S. Pat. No. 3,911,173(Sprague, Jr.) and U.S. Pat. No. 4,842,666 (Werenicz)) at a basis weightof about 0.116 g/m². The spirals have a width of about 1.9 cm (0.75 in)and either are positioned just next to each other or overlap slightly(less than 2 mm). The adhesive is preferably an adhesive such as isavailable from Findley Adhesives under the designation H2120.Alternatively, the side elastic member and any other components of thestretch laminates can be intermittently or continuously bonded to oneanother using heat bonding, pressure bonding, ultrasonic bonding,dynamic mechanical bonding, or any other method as is known in the art.

After the side elastic member 70 is operatively joined to the extendedportion 72 of the inner barrier cuff 54 and the side extended portion23C and 23D of the nonwoven outer cover 23, at least a portion of theresultant composite stretch laminate is then subjected to mechanicalstretching sufficient to permanently elongate the non-elastic componentswhich are, for example, the extended portion 72 of the inner barriercuff 54 and the side extended portion 23C and 23D of the nonwoven outercover 23. The composite stretch laminate is then allowed to return toits substantially untensioned condition. The extensible ear 46 and 48 isthus formed into “zero strain” stretch laminates. (Alternatively, theside elastic member 70 could be operatively joined in a tensionedcondition and then subjected to mechanical stretching.) Herein “zerostrain” stretch laminate refers to a laminate comprised of at least twoplies of material which are secured to one another along at least aportion of their coextensive surfaces while in a substantiallyuntensioned (“zero strain”) condition; one of the plies comprising amaterial which is stretchable and elastomeric (i.e., will returnsubstantially to its untensioned dimensions after an applied tensileforce has been released) and a second ply which is elongatable (but notnecessarily elastomeric) so that upon stretching the second ply will be,at least to a degree, permanently elongated so that upon release of theapplied tensile forces, it will not fully return to its originalundeformed configuration. The resulting stretch laminate is therebyrendered elastically extensible, at least up to the point of initialstretching, in the direction of initial mechanical stretching.

Particularly preferred methods and apparatus used for making stretchlaminates utilize meshing corrugated rolls or plates to mechanicallystretch the components and are disclosed in U.S. Pat. No. 5,167,897,which issued to Weber et al. on Dec. 1, 1992; in U.S. Pat. No.5,156,793, which issued to Buell et al. on Oct. 20, 1990; in U.S. Pat.No. 5,143,679, which issued to Weber et al. on Sep. 1, 1992 and inEuropean Patent Application No. 98108290.2, entitled “Method andApparatus for Activating a Moving Web,” filed on Can 7, 1998 (ChristophJ. Schmitz et al.).

The side elastic member 70 is preferably joined to, more preferablydirectly secured to, the side portions 68B of the inner barrier film 68through an adhesive 76 as shown in FIG. 4. In a preferred embodiment,the side elastic member 70 is joined to the side portions 68B of theinner barrier film 68 at the outer-facing surface 77. In an alternativeembodiment, the side elastic member 70 can be joined to the sideportions 68B of the inner barrier film 68 at the body-facing surface 79.Preferably, the adhesive 76 is applied as a bead. The adhesive 76 can beapplied as a spiral. In a preferred embodiment, the adhesive 76 is aflexible adhesive with an amorphous and crystallizing component. Such apreferred adhesive is supplied by the Findley Adhesive Company under thedesignation #H9224. Alternatively, the side elastic member 70 can bejoined to the side portions 68B of the inner barrier film 68 by anyother bonding means known in the art which comprise heat bonds, pressurebonds, ultrasonic bonds, dynamic mechanical bonds, or combinations ofthese attachment means.

The side elastic member 70 used for extensible ear 46 and 48, referringto FIG. 6, comprises the side elastomeric material 124. The side elasticmaterial 70 can further include one of, preferably both of a firstcoverstock layer 122 and a second coverstock layer 126. Alternatively,the side elastic material 70 can not include any additional layer.

The side elastomeric material 124 has a first surface 150 and a secondsurface 152 opposing the first surface 150, and a first coverstock layer122 which is joined to the first surface 150 of the side elastomericmaterial 124. In a preferred embodiment, the first coverstock layer 122is joined to the first surface 150 of the side elastomeric material 124by an adhesive. More preferably, the side elastic member 70 furthercomprises a second coverstock layer 126 which is joined to the secondsurface 152 of the side elastomeric material 124 by an adhesive 164. Theside elastomeric material 124 provides a good fitness by generating theoptimal retention (or sustained) force at the side area of the wearer.Preferably, the side elastomeric material 124 is extensible in at leastone direction, preferably in a direction having a vector component inthe lateral direction to generate a retention (or sustained) force thatis optimal to prevent the pull-on diaper 20 from drooping, sagging, orsliding down from its position on the torso without causing undesiredred marking on the skin of the wearer.

The side elastomeric material 124 can be formed in a wide variety ofsizes, forms, and shapes. In a preferred embodiment, the sideelastomeric material 124 is in the form of a continuous plane layer.Preferred forms of continuous plane layer include a scrim, a perforated(or apertured formed) film, an elastomeric woven or nonwoven, and thelike. In an alternative embodiment, the side elastomeric material 124 isin the form of strands (or strings) which are not connected each otherto form a continuous plane layer. The continuous plane layer can takeany shape that can be suitably provided in the ear panels. Preferredshapes of continuous plane layer include a quadrilateral including arectangle and a square, a trapezoid, and the other polygons.

Elastomeric materials which have been found to be especially suitablefor the side elastomeric material 124 are styrenic block copolymer basedscrim materials, perforated (or apertured) elastic films, strands,preferably with a thickness of from about 0.05 mm to about 1.0 mm (0.002inch-0.039 inch). Other suitable elastomeric materials for the sideelastomeric material 124 include “live” synthetic or natural rubber,other synthetic or natural rubber foams, elastomeric films (includingheat shrinkable elastomeric films), elastomeric woven or nonwoven webs;elastomeric composites, or the like.

The extensibility properties of the side elastomeric material 124 suchas the First Cycle Extension Force at 100% Extension (FCEF100%), theFirst Cycle Extension Force at 200% Extension (FCEF200%), the SecondCycle Recovery Force at 50% Extension (SCRF50%) and sustained load at50% after 10-12 hours are important considerations in the performance ofdisposable garments. The side elastomeric material 124 preferably hasextensibility properties within the ranges defined herein. The FCEF100%and the FCEF200% are measures of the overall perceived “stretchiness”during application/removal of disposable garments. These two propertiesalso affect the ability of the applicator to achieve a suitable degreeof application stretch. A side elastomeric material 124 with arelatively high FCEF100% and FCEF200% can cause difficulty in applyingthe disposable garment onto the wearer. On the other hand, a sideelastomeric material 124 with a relatively low FCEF100% and FCEF200% cannot achieve a suitable level of body fitting/conformity. The SCRF50%also closely relates to the body fitting/conformity of disposablegarments for the wearer. A side elastomeric material 124 with arelatively high SCRF50% tends to cause red marking on the skin of thewearer and can be uncomfortable for the wearer during usage. A sideelastomeric material 124 with a relatively low SCRF50% can not provideenough elastic force to keep the diaper in place on tie wearer or cannot provide good body fit. The sustained load at 50% evaluates the forcedecay over time. This should be limited or substantial sagging willresult. The values of FCEF100%, FCEF200%, and SCRF50% can be measured byusing a tensile tester. The tensile tester comprises an upper jaw and alower jaw that is located below the upper jaw. The upper jaw is movableand is connected to an extension force measuring means. The lower jaw isfixed on a desk (or floor). A test specimen (i.e., the elastomericmaterial to be measured) which has about 2.54 cm (1.0 inch) in width andabout 12.75 cm (5 inches) in length is prepared and clamped between theupper jaw and the lower jaw so that the effective specimen length (L)(i.e., gauge length) is about 2.54 cm (1.0 inch). The extension force isapplied to the test specimen through the upper jaw. When no extensionforce is applied to the test specimen, the test specimen is in itsuntensioned length. A tensile tester suitable for use herein isavailable from Instron Corporation (100 Royall Street, Canton, Mass.02021, U.S.A.) as Code No. Instron 5564.

In preferred embodiments, the FCEF100% of the side elastomeric material124 is at least about 100 grams/inch. More preferably, the FCEF100% isbetween about 120 to about 220 grams/inch, most preferably between about150 grams/inch and 190 grams/inch. The FCEF200% is preferably betweenabout 160 grams/inch and about 450 grams/inch, more preferably betweenabout 180 grams/inch and about 300 grams/inch, and yet more preferablybetween about 200 grams/inch and about 240 grams/inch. The SCRF50% ofthe side elastomeric material 124 is preferably between about 40grams/inch and about 130 grams/inch, more preferably between about 65grams/inch and about 105 grams/inch, and yet more preferably betweenabout 75 grams/inch and about 95 grams/inch. The sustained load at 50%is preferably between about 40 grams/inch and about 130 grams/inch, morepreferably between about 65 grams/inch and about 105 grams/inch, and yetmore preferably between about 75 grams/inch and about 95 grams/inch.

In the preferred embodiment shown in FIG. 6, the elastomeric scrim 124has a plurality of first strands 125 and a plurality of second strands127. The plurality of first strands 125 intersect the plurality ofsecond strands 127 at nodes 130 at a predetermined angle α, forming anet-like open structure having a plurality of apertures 132. Eachaperture 132 is defined by at least two adjacent first strands and atleast two adjacent second strands, so that the apertures 132 aresubstantially rectangular in shape. Other configurations of theapertures 132, such as parallelograms, squares, or circular arcsegments, can also be provided. Preferably, the first and second strands125 and 127 are substantially straight and substantially parallel to oneanother. Preferably, the first strands 125 intersect the second strands127 at nodes 130 such that the angle α is about 90 degrees. The firstand second strands 125 and 127 are preferably joined or bonded at nodes130. A preferred elastomeric scrim 124 is manufactured by the ConwedPlastics Company under the designation XO2514. This material has about12 elastic strands per inch in the structural direction B (i.e., thefirst strands 125) and about 7 elastic strands per inch in thestructural direction D (i.e., the second strands 127).

In another embodiment elastomeric material 124 can include a porous,macroscopically-expanded, three-dimensional elastomeric apertured web.The detail of such a structure and the method to manufacture isdisclosed in U.S. patent application Ser. No. 08/816,106, filed Mar. 14,1997. A preferred porous elastomeric material is manufactured byTredegar Film Products under the designation X-25007. The apertures canhave any desired shape. Preferably, the apertures have a shape having amajor axis and a minor axis perpendicular to each other, such as an ovalshape, and the major axis is preferably oriented generally orthogonal toapplied strain-induced stresses.

In the embodiment shown in FIG. 6, the side elastic member 70 comprisesfirst and second coverstock layers 122 and 126, and side elastomericmaterial 124 disposed in the first and second coverstock layers 122 and126. The first coverstock layer 122 has an inner surface 142 and anouter surface 144. The inner surface 142 of the first coverstock layer122 is the surface that is positioned faging the side elastomericmaterial 124. The second coverstock layer 126 also has an inner surface146 and an outer surface 148. The inner surface 146 of the secondcoverstock layer 126 is the surface that is positioned facing the sideelastomeric material 124. The side elastomeric material 124 also has twoplanar surfaces, first surface 150 and second surface 152, each of whichis substantially parallel with the planes of the first and secondcoverstock layers 122 and 126. The first surface 150 is that planarsurface of the side elastomeric material 124 that is most closelyadjacent with the inner surface 142 of first coverstock layer 122. Thesecond surface 152 is that planar surface of side elastomeric material124 that is most closely adjacent to the inner surface 146 of the secondcoverstock layer 126.

Since the side elastic member 70 will be subjected to mechanicalstretching before and during use, the first and second coverstock layers122 and 126 preferably has a relatively high elongation at breaking, andare more preferably stretchable or elongatable, yet more preferablydrawable (but not necessarily elastomeric), without undue and preferablywithout any, tearing or ripping. Further, the first and secondcoverstock layers 122 and 126 are preferably compliant, soft feeling,and non-irritating to the wearer's skin and give the article the feeland comfort of a cloth garment. Suitable materials for the first andsecond coverstock layers 122 and 126 can be manufactured from a widerange of materials such as plastic films, apertured plastic films, wovenor nonwoven webs of natural fibers (e.g., wood or cotton fibers),synthetic fibers (e.g., polyolefins, polyamides, polyester,polyethylene, or polypropylene fibers), or a combination of naturaland/or synthetic fibers, or coated woven or nonwoven webs.

Preferably, each of the first and second coverstock layers 122 and 126is an identical nonwoven material. An exemplary preferred nonwovenmaterial is manufactured by the FiberWeb Company under the designationDAPP-S tex having a basis weight in the range of 18-35 g/m². Thenonwoven can be consolidated or not consolidated. Preferably, thenonwoven is consolidated for the use of a coverstock layer for anelastomeric scrim. This material has a basis weight in the range of18-35 g/m² before consolidation and a basis weight in the range of about40-70 g/m² after consolidation. As used herein, “basis weight” is theweight per unit area of planar web material, one square meter in thisinstance. Alternatively, highly strainable nonwoven materials can beused. Alternatively, the first and second coverstock layers 122 and 126need not be of identical materials, as long as the desired performancerequirements, such as elastic performance, softness, flexibility,breathability and durability, are met. As used herein, “consolidatednonwoven material” refers to a nonwoven material that has been gatheredor necked under mechanical tension in the structural direction D so thatthe material can elongate in the structural direction D under low force.

Referring to FIG. 1, the pull-on diaper 20 further has the continuousextensible waist feature 60. The continuous extensible waist feature 60improved fit, ease of application and containment. The continuousextensible waist feature 60 is that portion or zone of the pull-ondiaper 20 which is intended to be elastically extensible and contract todynamically fit the wearers waist. The continuous extensible waistfeature 60 extends along the waistband panel 6 and 7. Preferably, thecontinuous extensible waist feature 60 comprises two separate elements;one continuous extensible waistband 57 positioned in the front region26, and the other continuous extensible waistband 59 positioned in theback region 28, although other pull-on diapers can be constructed with asingle continuous extensible waistband.

Referring to FIG. 5 as well, the continuous extensible waistband 57 and59 preferably comprises a waist elastic member 80 having the waistelastomeric material 200 (shown in FIG. 6) and an extended portion of atleast one of the plurality of layers disposed associated with theabsorbent core 25, such as the topsheet 24 and the backsheet 22(although FIG. 5 shows only the structures in the front region 26,preferably the structures in the back region 28 are the same or similarto those in the front region 26). Preferably the continuous extensiblewaistband 57 and 59 is elastically extensible in at least the lateraldirection, more preferably both in the lateral and longitudinaldirections. In a preferred embodiment, the waistband panel 6 and 7 isrendered extensible at least in the entire lateral length of thewaistband panel 6 and 7 to form the continuous extensible waistband 57and 59 by the waist elastic member 80.

In the embodiment shown in FIG. 3, the waist elastic member 80 canextend into the seam panel 12 and 13 so that the continuous extensiblewaistband 57 and the continuous extensible waistband 59 are anchoredeach other at the seam 32, and the waist elastic material 80 in thefront region 26 and the elastic material 80 in the back region 28 areanchored at the seam 32 (FIG. 5 also shows the waist elastic member 80which extends into the seam panel 12 and 13, though the seam panel 12and 13 is not shown in FIG. 5). The continuous extensible waistband 57and 59 forms one continuous extensible waist feature 60 in an assembledconfiguration of the pull-on diaper 20 as shown in FIG. 1.

The continuous extensible waistband 57 and 59 can be formed by unitaryelements of the pull-on diaper 20 (i.e., they are not separatelymanipulative elements secured to the pull-on diaper 20, but rather areformed from and are extended portions of one or more of the variouslayers of the pull-on diaper). In a preferred embodiment, each of thecontinuous extensible waistband 57 and 59 comprises a projected memberof the chassis 41. Preferably, the continuous extensible waistband 57and 59 comprises at least one unitary element or a continuous sheetmaterial that forms a part of the chassis 41 and continuously extendsinto the continuous extensible waistband 57 and 59. Alternatively, thecontinuous extensible waistband 57 and 59 can be discrete members thatdo not have any unitary element that forms a part of the chassis 41. Thecontinuous extensible waistband 57 and 59 can be formed by joining thediscrete members to the waist portions of the chassis 41.

The continuous extensible waistband 57 and 59 comprises the waistelastic member 80 and an extended portion of at least one of theplurality of layers disposed associated with the absorbent core 25, suchas the topsheet 24 and the backsheet 22. If an additional layer, such asthe inner barrier cuff 54 or an additional liquid absorbing tissuelayer, is added associated with the absorbent core 25, the additionallayer can form a part of the continuous extensible waistband 57 and 59.In a preferred embodiment shown in FIG. 7, the side portion 57B of thecontinuous extensible waistband 57 comprises a lamination of an extendedportion 72 of the inner barrier cuff 54, the end extended portion 23A ofthe nonwoven outer cover 23, and a side part of the waist elastic member80. The central portion 57A of the extensible waistband 57 comprises alamination of the end extended portion 24A of the topsheet 24, the endextended portion 23A of the nonwoven outer cover 23, and a center partof the waist elastic member 80 (although FIG. 5 shows only thestructures in the front region 26, preferably the structures in the backregion 28 are the same or similar to those in the front region 26).However, in the embodiment, the inner barrier film 68 does not extendinto the continuous extensible waistband 57. Alternatively, the innerbarrier cuff 54, the topsheet 24, and/or the nonwoven outer cover 23 cannot extend into the continuous extensible waistband 57. The extendedportion 72 of the inner barrier cuff 54 also can not extend into thecontinuous extensible waistband 57. If both of the topsheet 24 and thenonwoven outer cover 23 do not extend into the continuous extensiblewaistband 57, the continuous extensible waistband 57 can comprise anextended portion of the inner barrier film 68 and the waist elasticmember 80.

The waist elastic member 80 overlies a portion of the body-facingsurface of the pull-on diaper 20. The waist elastic member 80 can beoperatively joined to the extended portions 72 of the inner barriercuffs 54, the end extended portion 23A of the nonwoven outer cover 23,and the end extended portion 24A of the topsheet 24. The waist elasticmember 80 can be operatively joined thereto, by using either anintermittent bonding configuration or a substantially continuous bondingconfiguration. In a particularly preferred embodiment, the adhesiveselected is applied in a spiral pattern (such as is shown in U.S. Pat.No. 3,911,173 (Sprague, Jr.) and U.S. Pat. No. 4,842,666 (Werenicz)) ata basis weight of about 0.116 g/m². The spirals have a width of about1.9 cm (0.75 in) and either are positioned just next to each other oroverlap slightly (less than 2 mm). The adhesive is preferably anadhesive such as is available from Findley Adhesives under thedesignation H2120. Alternatively, the waist elastic member and any othercomponents of the stretch laminates can be intermittently orcontinuously bonded to one another using heat bonding, pressure bonding,ultrasonic bonding, dynamic mechanical bonding, or any other method asis known in the art.

The entire unstrained length of the waist elastic member 80 ispreferably prestrained in the lateral direction before operativelyjoined to the extended portions 72 of the left and right inner barriercuffs 54, the end extended portion 24A of the topsheet 24, and the endextended portion 23A of the nonwoven outer cover 23. The entireunstrained length of the waist elastic member 80 is prestrained in thelateral direction up to at least the original length of the waistbandpanel 6 and 7 of the chassis 41. The entire unstrained length of thewaist elastic member 80 can be further prestrained to extend into a partof the seam panel 12 and 13. In the embodiment, the waistband panel 6and 7 of the chassis 41 comprises the extended portions 72 of the leftand right inner barrier cuffs 54, the end extended portion 24A of thetopsheet 24, and the end extended portion 23A of the nonwoven outercover 23.

Herein “original length” refers to the length of a single material or acomposite material before being rendered elastically extensible andbefore being permanently mechanically stretched. Herein “prestrainedentire length” refers to the entire length of an elastic material undera condition where a part of or the entire length of the elastic materialis prestrained in the lateral direction.

In the embodiment, the original length of the waistband panel 6 and 7 isgenerally the same as the combined length of the extended portions 72 ofthe left and right inner barrier cuffs 54 and the end extended portion24A of the topsheet 24 under an assembled configuration before the waistelastic member 80 is joined thereto. The original length of thewaistband panel 6 and 7 is also generally the same as the length of theend extended portion 23A of the nonwoven outer cover 23 before the waistelastic member 80 is joined thereto. The waist elastic member 80 ispreferably prestrained in range of from 20 to 100% of its unstrained(i.e. untensioned) length. More preferably, the waist elastic member 80can be prestrained in range of from 40 to 80%. After the prestrainedwaist elastic member 80 is jkined, the waist elastic member 80 is thenallowed to return to their substantially untensioned condition with theother components, such as the extended portions 72 of the inner barriercuffs 54, the end extended portion 24A of the topsheet 24, and the endextended portion 23A of the nonwoven outer cover 23, joined to the waistelastic member 80. Thus the continuous extensible waistband 57 and 59 isformed that is extensible, from the untensioned length of the waistelastic member 80 at least to the original length of the waistband panel6 and 7 of the chassis 41.

Alternatively, only a part of the waist elastic member 80 can beprestrained before operatively joined to the extended portion of atleast one of the plurality of layers, such that the prestrained entirelength of the waist elastic member 80 in a condition where a part of thewaist elastic member 80 is prestrained is generally the same as theoriginal length of the waistband panel 6 and 7 of the chassis 41.Preferably, only a part of the waist elastic material 80, which extendsalong the lateral width X (shown in FIG. 3) of the absorbent core 25adjacent to the waist elastic material 80, can be prestrained.

Examples of extensible materials are disclosed in U.S. Pat. No.2,075,189, which issued to Galligan on Mar. 30, 1937; in U.S. Pat. No.3,025,199, which issued to Harwood on Mar. 13, 1962; in U.S. Pat. Nos.4,107,364 and 4,209,563, which issued to Sisson on Aug. 15, 1978, and onJun. 24, 1980, respectively; in U.S. Pat. No. 4,834,741, which issued toSabee on May 30, 1989; and in U.S. Pat. No. 5,151,092, which issued toBuell et al., on Sep. 29, 1992.

The continuous extensible waistband 57 and 59 is formed to beextensible, from the untensioned length of the waist elastic member 80at least up to the original length of the waistband panel 6 and 7 of thechassis 41. However, the waist elastic member 80 is usually joined tothe extended portion of at least one of the plurality of layers disposedassociated with the absorbent core 25, such as the topsheet 24 and thebacksheet 22 which are substantially non-elastic. Therefore, the waistelastic member 80 can extend only between the untensioned length of thewaist elastic member 80 and the original length of the waistband panel 6and 7 of the chassis 41, and can not extend beyond the original lengthof the waistband panel 6 and 7 of the chassis 41. This restricts theupper limit of the extension range of the continuous extensiblewaistband 57 and 59 (i.e., continuous extensible waist feature 60), evenif the waist elastomeric material 80 itself is capable of extendingbeyond the original length of the waistband panel 6 and 7 of the chassis41 or the prestrained entire length of the waist elastomeric material80. This restriction in the upper limit of the extension range does notallow enough extensibility for the continuous extensible waistband 57and 59. Therefore, when the pull-on diaper 20 is extended forapplication to the wearer, the pull-on diaper 20 can not provide enoughsize of waist opening or the applicator must apply much high force tothe pull-on diaper 20 to seek extensibility from other extensiblematerials in the pull-on diaper 20 to obtain enough size of waistopening. This can cause difficulty in applying the pull-on diaper to thewearer.

Therefore, the continuous extensible waistband 57 and 59 is renderedelastically extensible to provide greater range of extensibility (i.e.,extension range) beyond the original length of the waistband panel 6 and7 of the chassis 41 or the prestrained entire length of the waistelastic member 80. Namely, after the waist elastic member 80 isoperatively joined under a prestrained (tensioned) condition to theinner barrier cuff 54, the topsheet 24 and the nonwoven outer cover 23and before returning to their substantially untensioned condition, atleast a portion of, preferably the entire of the resultant compositestretch laminate (i.e., continuous extensible waistband 57 and 59) isthen subjected to mechanical stretching sufficient to permanentlyelongate the non-elastic components which are the extended portions 72of the left and right inner barrier cuffs 54, the end extended portion24A of the topsheet 24, the end extended portion 23A of the nonwovenouter cover 23, and the coverstock layers (if any) constituting a partof the waist elastic member 80. The composite stretch laminate is thenallowed to return to its substantially untensioned condition. Therefore,the waist elastic member 80 is extensible from the untensioned lengthbeyond the original length of the waistband panel 6 and 7 of the chassis41 at least up to the permanently elongated length of the non-elasticcomponents. This provides wider extension range for the continuousextensible waistband 57 and 59, thereby providing a benefit of ease ofapplication. Alternatively the waist elastic member 80 can be joined tothe inner barrier cuffs 54, the topsheet 24 and the nonwoven outer cover23 in a substantially untensioned (zero strain) condition so as to forma “zero strain” stretch laminate. Preferred apparatus and methods aredisclosed in U.S. Pat. No. 5,167,897 issued to Weber et al. on Dec. 1,1992; U.S. Pat. No. 5,156,793 issued to Buell et al. on Oct. 20, 1990;U.S. Pat. No. 5,143,679 issued to Weber et al. on Sep. 1, 1992 andEuropean Patent Application No. 98108290.2 titled “METHOD AND APPARATUSFOR ACTIVATING A MOVING WEB” filed on Can 7, 1998 (Christoph J. Schmitzet al.).

The waist elastic member 80 comprises the waist elastomeric material200, which can use the same material/structure as the side elastomericmaterial 124. Alternatively, the waist elastomeric material 200 can usematerial/structure different from the side elastomeric material 124. Thewaist elastic member 80 can further include one of, or both of a firstcoverstock layer 202 and a second coverstock layer 204. The structure ofthe waist elastic member 80 can be the same or similar to that of theside elastic member 70. The structure, materials and/or properties ofthe coverstock layers 202 and 204 can be the same or similar to those ofthe coverstock layers 122 and 126, or can be different from those.Further, the method to join the waist elastomeric material 200 to thecoverstock layers 202 and 204 can be the same or similar to the methodof those described for the ear panel member 70 above, or can bedifferent from those. In a preferred embodiment, the waist elasticmember 80 comprises the waist elastomeric material 200 and one layer ofthe coverstock layer 202 or 204. In such a case, the waist elastomericmaterial 200 is disposed facing the inner barrier cuffs 54 and thetopsheet 27, and the coverstock layer 202 or 204 is disposed so as toface and contact the wearer's body. such that the wearer's skin is notdirectly pressed by the waist elastomeric material 200 thereby reducingthe incidence of red marking on the skin.

In one embodiment, the waist elastic member 80 can comprise the waistelastomeric material 200 and one layer of the coverstock layer 202 or204. In one case, the waist elastomeric material 200 is disposed facingthe inner barrier cuffs 54 and the topsheet 24, and the coverstock layer202 or 204 is disposed facing the nonwoven outer cover 23. Thisdisposition of the coverstock layer tends to inhibit the waistelastomeric material 200 is seen through from the outside because onelayer (coverstock layer) is added to interpose between the waistelastomeric material 200 and the nonwoven outer cover 23. In anothercase, the waist elastomeric material 200 is disposed facing the nonwovenouter cover 23, and the coverstock layer 202 or 204 is disposed facingthe inner barrier cuffs 54 and the topsheet 27. This disposition of thecoverstock layer tends to reduce the incidence of red marking on theskin because one layer (coverstock layer) is added to interpose betweenthe waist elastomeric material 200 and the skin of the wearer. In bothcases, because one of the coverstock layers is eliminated (compared withtwo layers of the coverstock layers), bulkiness in the continuousextensible waistband 57 reduces. Further, breathability at thecontinuous extensible waistband 57 enhances because of less materialtherein, In addition, the continuous extensible waistband 57 becomes tohave more available extensibility. The continuous extensible waistband57 is formed by the waist elastic member 80 comprising the waistelastomeric material 200 which is prestrained and then returned to theoriginal untensioned condition in a preferred embodiment. When the waistelastomeric material 200 returns to its original untensioned condition,the other components joined to the waist elastomeric material 200 tendsto inhibit the waist elastomeric material 200 to return its originaluntensioned length. Therefore, the waist elastomeric material 200 cannot utilize the whole extensibility. However, in the embodimentdescribed above, since bulkiness in the continuous extensible waistband57 reduces, the waist elastomeric material 200 can return as close asits original untensioned length. Therefore, the waist elastomericmaterial 200 becomes to have more available extensibility.

Alternatively, the waist elastic member 80 can comprise one layer of thewaist elastomeric material 200 without any coverstock layers. In theside portions 57B of the extensible waistband 57, the waist elastomericmaterial 200 is interposed and joined directly between the extendedportions 72 of the inner barrier cuffs 72 and the end extended portion23A of the nonwoven outer cover 23. In the central portion 57A, thewaist elastomeric material 200 is interposed and joined directly betweenthe end extended portion 24A of the topsheet 24 and the nonwoven outercover 23. This structure is also useful to reduce bulkiness, to enhancebreathability, and to have more available extensibility, in theextensible waistband 57.

The side elastic member 70 and the waist elastic member 80 consist ofseparate elements and both members 70 and 80 are preferably disposed notto overlap to each other in the longitudinal direction. However, bothmembers 70 and 80 are preferably disposed without a substantial gaptherebetween such that the members 70 and 80 form a compositeelastomeric network in the extensible ears 46 and 48.

Herein “composite elastomeric network” refers to a zone or area wheretwo or more separate elastomeric materials substantially continue withno gap between the elastomeric materials or with a predeterminedinterval thereby exhibiting a behavior of extensibility like a singleelastomeric material.

Preferably, both members 70 and 80 are disposed with no gap. Therefore,it is perceived that the extensible ear 46 and 48 and the side portion57B and 59B of the continuous extensible waistband 57 and 59 comprise acontinuous single elastomeric material between the waist opening 36 andthe leg openings in an assembled configuration of the pull-on diaper 20.The side elastic member 70 and the waist elastic member 80 consist ofseparate elements; therefore the side elastomeric material 124 and thewaist elastomeric material 200 also consist of separate elements.

The separated structure allows the design of the side elastomericmaterial 124 and the waist elastomeric material 200 using differentmaterials in each components, so this allows different properties ofextensibility such as force versus extension curve for different partsof the pull-on diaper 20. The separated structure also allows use of theside elastomeric material 124 and the waist elastomeric material 200 indifferent conditions, such as in a prestrained (tensioned) condition oruntensioned condition. This allows differentiation of the force requiredto extend different parts of the pull-on diaper 20 up to the same lengthor equalize force required to extend different parts up to the differentlength, thereby adjusting the pressure applied to the skin of thewearer. For example, the pull-on diaper 20 can have a waist elastomericmaterial 200 provided with high extensibility at low force such that thecontinuous extensible waist feature 60 is extended easily by low forceapplied by the applicator for ease of application of the pull-on diaper20 while the pull-on diaper 20 can have a side elastomeric material 124generating force required for sustained fit at the extensible ear 46 and48, but the force can not give red marking to the skin. In oneembodiment, the continuous extensible waist feature 60 comprising thewaist elastomeric material 200 is designed to have extensibility of atleast 100% while the extensible ear 46 and 48 comprising the sideelastomeric material 124 is designed to have force between 40 g/inch and130 g/inch when the extensible ear 46 and 48 is extended up to 50% (moreconcretely, at SCRF50%).

Both the side elastic member 70 and the waist elastic member 80 aredisposed not to overlap to each other in the longitudinal direction;therefore, the side elastomeric material 124 and the waist elastomericmaterial 200 also do not overlap. Because the side elastic member 70 andthe waist elastic member 80 are not structurally overlapped, each member70 and 80 comprises a single material of extensibility; therefore it hassubstantially homogeneous property of extensibility. This allows theapplicator to extend the pull-on diaper 20 smoothly without feeling thechange of force applied during extending for application of the pull-ondiaper.

The seams 32 each joins the seam panels 12 and 13, thereby joining thecorresponding portions of the extensible ears 46 and 48, and therebyforming two leg openings 34 and one waist opening 36. The front and backextensible ears 46 and 48 are seamed, preferably, along the outer sideedges 46D and 48D, in an overlapped manner to make an overlapped seamstructure. Alternatively, the front and back extensible ears 46 and 48can be seamed in a butt seam manner (not shown) known to those skilledin the art. The bonding of the seams 32 can be performed by any suitablemeans known in the art appropriate for the specific materials employedin the front and back extensible ears 46 and 48. Thus, sonic sealing,heat sealing, pressure bonding, adhesive or cohesive bonding, sewing,autogeneous bonding, and the like can be appropriate techniques.Preferably, the seam panels 12 and 13 are joined by a predeterminedpattern of heat/pressure or ultrasonic welds which withstands theforces- and stresses generated on the pull-on diaper 20 during wear. Theseams 32 also connect the continuous extensible waistbands 57 and 59 toform the continuous extensible waist feature 60 about the waist opening36. When the side elastic member 70 and the waist elastic member 80extend into the seam panel 12 and 13, the seams 32 anchor the sideelastic member 70 in the front region 26 to the side elastic member 70in the back region 28 and anchor the waist elastic member 80 in thefront region 26 to the waist elastic member 80 in the back region 28.Examples of seams are disclosed in U.S. Pat. No. 5,569,234 issued toBuell, et al. on Oct. 29, 1996, U.S. Pat. No. 5,607,537 issued toJohnson et al. on Mar. 4, 1997, U.S. Pat. No. 5,662,638 issued toJohnson et al. on Sep. 2, 1997, and U.S. Pat. No. 5,685,874 issued toBuell et al. on Nov. 11, 1997. Preferable seams are disclosed inEuropean Patent Application No. 96118654.1 titled “Thermal Joining ofWebs” filed on Nov. 21, 1996 (Christoph J. Schmitz).

In a preferred embodiment, the outer side edge 46D and 48D isnon-parallel to the inner side edge 46C and 48C and is non-parallel tothe longitudinal centerline 100. The outer side edge 46D and 48Dprojects laterally outwardly proximate the lower end edge 46B and 48B.The extensible ear 46 and 48 has a lateral width L1 between the innerside edge 46C and 48C and the outer side edge 46D and 48D proximate thelower end edge 46B and 48B greater than a lateral width L2 between theinner side edge 46C and 48C and the outer side edge 46D and 48Dproximate the higher end edge 46A and 48A. Therefore, the availableelastomeric material quantity in the lateral direction of the extensibleear 46 and 48 is greater proximate the lower en edge 46B and 48B thanproximate the higher end edge 46A and 48A. The extensibility proximatethe lower end edge 46B and 48B is enhanced. In addition, because bothextensible ear 46 and extensible ear 48 have greater lateral width(i.e., available elastomeric material quantity) proximate the lower endedge 46B and 48B, lateral width (i.e., available elastomeric materialquantity) further becomes greater proximate the lower end edge 46 B and48B by combining the extensible ear 46 and the extensible ear 48.Because of the configuration being greater in width proximate the lowerend edge 46B and 48B, the pull-on diaper has more elastomeric materialquantity available about the leg openings while the pull-on diapermaintains elastomeric material quantity about the waist opening.Therefore, the pull-on diaper does not give too high pressure to theskin causing the negative skin incidence about the leg openings whilemaintaining a sustained fit about the waist opening.

Further, as explained hereinabove, the waist elastic member 80 is joinedto the waistband panel 6 and 7 of the chassis 41 in a tensioned(prestrained) condition and allowed to return to the substantiallyuntensioned condition while the side elastic member 70 is joined to theextensible ear 46 and 48 in an untensioned condition. Therefore, thecircumference of the pull-on diaper 20 about the continuous extensiblewaist feature 60 further becomes smaller under an untensioned conditionthan the circumference of the pull-on diaper 20 through a portion of theextensible ear 46 and 48. This configuration further improves asustained fit about the waist opening while reducing the skin incidenceabout the leg openings. Herein “circumferential direction” refers to adirection along the waist opening in an assembled configuration of thepull-on diaper. Herein “circumference” refers to a length of thepull-diaper along the circumferential direction.

The continuous belt zone 38 is formed by the front and back extensibleears 46 and 48, a part of the chassis 41, and the continuous extensiblewaist feature 60 as shown in FIG. 1. The continuous belt zone is thatportion or a belt-like zone of the pull-on diaper that is extensiblesuch that the circumference of the continuous belt zone is extended forapplication of the pull-on diaper 20. When the pull-on diaper 20 isapplied to the wearer, the pull-on diaper 20 must be extended to securewider waist opening and wider leg opening for ease of application of thepull-on diaper 20. The continuous belt zone 38 is that portion capableof being extended. The continuous belt zone 38 is, in an assembledconfiguration shown in FIG. 1, encompassed by the waist edge 151 and 155of the pull-on diaper 20, the leg edge 153 and 156, the lateral edge 159of the crotch region 30 in the front region 26 and the back region 28.The continuous belt zone 38 has the least height typically at the earpanels. In the embodiment shown in FIG. 1, the least height of thecontinuous belt zone 38 is measured along the seams 32. The continuousbelt zone 38 also has a continuous lowermost line 35, which is notinterrupted by the leg openings 34, but is the closest to the legopenings 34. The continuous belt zone 38 has two portions, a continuouswaist belt zone 37 in which the continuous extensible waist feature 60extends, and a continuous lower belt zone 39 in which the extensibleears 46 and 48 and a part of the chassis 41 extend. In a preferredembodiment, the continuous waist belt zone 37 conforms with thecontinuous extensible waist feature 60.

In one preferred embodiment where the pull-on diaper shown in FIG. 3becomes an assembled configuration as shown in FIG. 1, the initialcircumference of the continuous belt zone 38 along the waist edge 151and 155 can be from 200 mm to 500 mm in an untensioned condition,preferably from 250 mm to 400 mm. The circumference of the continuousbelt zone 38 along the waist edge 151 and 155 extends up to at least 650mm, preferably at least 700 mm, more preferably at least 750 mm(extended circumference). The circumference of the continuous belt zone38 along the line 35 can be from 300 mm to 550 mm, preferably from 350mm to 500 mm. The least height of the continuous belt zone 38 measuredalong the seams 32 can be from 50 mm to 150 mm, preferably from 80 mm to120 mm. The height of the continuous waist belt zone 37 (i.e.,continuous extensible waist feature 60) can be from 5 mm to 40 mm,preferably from 15 mm to 30 mm. The combined lateral length of theextensible ears 46 and 48 in one side of the pull-on diaper 20 along theline 35 is from 50 mm to 120 mm, preferably from 60 mm to 100 mm.

The pull-on diaper having a configuration shown in FIG. 3, when itbecomes an assembled configuration, lowers the pressure to the skin ofthe wearer locally especially about the leg openings 34 because theextensible ear 46 and 48 has greater lateral width (availableextensibility in the lateral direction) proximate the lower end edge 46Band 48B. If necessary, the side elastomeric material 124 can use amaterial having lower SCRF50% force to further lower the pressure aboutthe leg openings 34. However, lowering the SCRF50% force about the legopenings 34 can result in losing sustained fit for the whole pull-ondiaper. Therefore, raising the pressure about the waist opening 36 canbe necessary to achieve a sustained fit for the whole pull-on diaper.This can be achieved by prestraining only the waist elastomeric material200 before joining to the waistband panel 6 and 7. In addition, thewaist elastomeric material 200 can use a material having a higherSCRF50% force to further raise the pressure about the waist opening 36.These combinations of force distributions allow the pull-on diaper toachieve a sustained fit about the waist opening with less incidence ofred marking on the skin about the leg openings. Alternatively, thepull-on diaper having a configuration shown in FIG. 3, when it becomesan assembled configuration, can provide a sustained fit about the legopenings and less incidence of red marking on the skin about the waistopening. This can be achieved, for example, using a material havinglower SCRF50% force for the waist elastomeric material 200 to lower thepressure about the waist opening 36. The side elastorneric material 124can use a material having a lower SCRF50% force. Further, the sideelastomeric material 124 can be prestrained before joining to the earpanel 6 and 7.

The continuous belt zone 38 contributes to dynamically create fit forcein the pull-on diaper 20 when positioned on the wearer, to maintain thepull-on diaper 20 on the wearer. Although higher fit force generated bythe continuous belt zone 38 is preferable for sustained fit for thepull-on diaper, the continuous belt zone 38 generating the higher fitforce causes difficulty in applying the pull-on diaper to the wearerbecause the applicator of the pull-on diaper must apply higher force tothe pull-on diaper to extend the continuous belt zone 38 such that thewider waist opening and wider leg openings are secured. Because thecontinuous belt zone 38 comprises the side elastomeric material 124 andthe waist elastomeric material 200, both elastomeric materials must beextended during the process of pulling on the pull-on diaper. Therefore,the property of extensibility of the continuous belt zone 38 includingthe side and waist elastomeric materials are more important than thoseof a solo continuous extensible waist feature 60 and/or those of a soloextensible ear 46 and 48, though the property of extensibility of a solocontinuous extensible waist feature 60 and/or a solo extensible ear 46and 48 are still important. U.S. Pat. No. 5,601,547, which issued onFeb. 11, 1997, to Kato, et al. discloses a waist elastic system withimproved modulus of elasticity for a child's training pant providing amore comfortable fit and improved ease of use. However, that patent isdirected only to improvement of the waist elastic system.

The continuous belt zone 38 is extensible in the extension range from aninitial extension (i.e., 0%). The extension is calculated from theequation:

((extended circumference−initial circumference)/initialcircumference)×100

and expressed in the unit of % (percent). The initial circumference ofthe continuous belt zone 38 is the circumference under an untensionedcondition of the continuous belt zone 38. The extended circumference isthe circumference under an extended condition of the continuous beltzone 38. The wider extension range allows securing the wider waistopening and the wider leg openings for application of the pull-on diaper20. The wider extended circumference allows securing the wider spacebetween the extended pull-on diaper and the body of the wearer forapplication of the pull-on diaper 20. The circumference of thecontinuous belt zone 38 is the circumference measured along the waistborder of the continuous belt zone 38 (i.e., the waist edges 151 and 155of the continuous extensible waist feature 60).

In order to provide a benefit of ease of application of the pull-ondiaper (i.e., wider waist opening and wider leg openings), the initialcircumference of the continuous belt zone 38 of the pull-on diaper canbe between about 220 mm and about 500 mm, and the extended circumferenceof the continuous belt zone 38 of the pull-on diaper is at least about650 mm. More specifically, the initial circumference of the continuousbelt zone 38 of the pull-on diaper designed to fit toddlers weighingfrom about 7 kg to about 10 kg is between about 220 mm and about 460 mm,preferably about 250 mm and about 360 mm. The initial circumference ofthe continuous belt zone 38 of the pull-on diaper designed to fittoddlers weighing from about 9 kg to about 14 kg is between about 240 mmand about 480 mm, preferably about 270 mm and about 380 mm. The initialcircumference of the continuous belt zone 38 of the pull-on diaperdesigned to fit toddlers weighing about 13 kg or above is between about260 mm and about 500 mm, preferably about 290 mm and about 400 mm. Theextended circumference of the continuous belt$zone 38 of the pull-ondiaper designed to fit toddlers weighing from about 7 kg to about 10 kgis at least about 650 mm, preferably about 700 mm. The extendedcircumference of the continuous belt zone 38 of the pull-on diaperdesigned to fit toddlers weighing from about 9 kg to about 14 kg is atleast about 700 mm, preferably about 750 mm. The extended circumferenceof the continuous belt zone 38 of the pull-on diaper designed to fittoddlers weighing about 13 kg or above is at least about 750 mm,preferably about 800 mm. The pull-on diaper has the extension range upto at least the extension of about 125%, preferably about 135%, morepreferably about 150%.

The continuous belt zone 38 also has a force versus extension curve inthe extension range and a modulus of extensibility in the extensionrange. The force versus extension curve represents a relationship of aforce required to extend the continuous belt zone 38 and an extension ofthe continuous belt zone 38. The modulus of extensibility represents arate of force change to extension change and is expressed in the unit ofg/% extension (grams/percent extension). The method to obtain themodulus of extensibility is set forth below. The higher modulus ofextensibility means higher rate of force change to extend the continuousbelt zone 38. When modulus of extensibility becomes dramatically high,the applicator recognizes that part as a limitation of extension.Conversely, the lower modulus of extensibility means lower rate of forcechange to extend the continuous belt zone 38. This allows the applicatorto extend the continuous belt zone 38 without adding higher force, andthe applicator can not recognize the limitation of extension. Therefore,it is preferable the continuous belt zone 38 has lower modulus ofextensibility at the extended circumference for application of thepull-on diaper. In addition, the lower force to extend the pull-ondiaper up to the extended circumference for application of the pull-ondiaper is preferable. In order to provide a benefit of ease ofapplication of the pull-on diaper (i.e., lower force to obtain theextension for application of the pull-on diaper and lower modulus ofextensibility at the extension for application of the pull-on diaper),the modulus of extensibility at the extension of 125% is not greaterthan about 150 g/% extension, preferably not greater than about 120 g/%extension, more preferably not greater than about 100 g/% extension. Themodulus of extensibility in the extension range up to the extension of125% is preferably not greater than about 150 g/% extension, morepreferably not greater than about 120 g/% extension. The modulus ofextensibility at the extension of 135% is not greater than about 200 g/%extension, preferably not greater than about 175 g/% extension, morepreferably not greater than about 150 g/% extension. The modulus ofextensibility in the extension range up to the extension of 135% ispreferably not greater than about 200 g/% extension, more preferably notgreater than about 175 g/% extension. The modulus of extensibility atthe extension of 150% is preferably not greater than about 300 g/%extension, more preferably not greater than about 250 g/% extension. Theforce to obtain the extension of 125% is preferably not greater thanabout 5,000 g, more preferably not greater than about 4,500 g. The forceto obtain the extension of 135% is preferably not greater than about6,000 g, more preferably not greater than about 5,500 g. The force toobtain the extension of 150% is preferably not greater than about 9,000g, more preferably not greater than about 8,000 g.

FIG. 7 shows one preferred example of the force versus extension curvesof the continuous belt zone 38 of the pull-on diaper. FIG. 8 shows themodulus of extensibility versus extension curve of the example shown inFIG. 7. The methods to obtain a force versus extension curve of thecontinuous belt zone 38 and a modulus of extensibility versus extensioncurve are set forth below.

The methods to obtain a force versus extension curve of the continuousbelt zone and a modulus of extensibility versus extension curve are setforth below. This method is a modified ultimate tensile test methodcontained within the “Sintech TestWorks” software package for measuringa force versus extension curve. This measurement is basically designedto simulate the applicator habit in putting a pull-on diaper on thewearer by using the Instron force tester and two horizontal bars in theplace of the jaws starting from 0 g force to 10,000 g force or when thediaper breaks, which represents the ultimate force applied to thecontinuous belt zone. The method gives “force versus extension” curvefrom the untensioned condition up to the ultimate tensile of the diaper.The force versus extension data generated as described above can then beconverted to “modulus of extensibility versus extension.”

This test method requires sample preparation as described below.

(1) The sample diaper to be tested should be taken from the bag

(2) Measure the diaper inside circumference at the waist edge of thediaper using measuring tape without stretching diaper during themeasurement (Untensioned Diaper Circumference)

This test method involves the following equipment below.

(1) Tensile/Cycle Tester Instron Model 5564 (2) Operation SoftwareSintech TestWorks version 3.0 (3) Loadcell Instron Static Loadcell 100N(4) Jaw 20 mm diameter × 150 mm length Teflon coated bar mountedhorizontally to upper and lower jaws

This test method is performed with the setting below.

(1) Test Method: Tensile

(2) Travel Speed: 20 inch/minute

(3) Gauge Length: distance of the center of the upper bar and the lowerbar is calculated as below

(Gauge Length)=(Untensioned Diaper Circumference)/2-30 mm

(4) # of Cycle: 1 cycle

(5) Break Sensitivity: 75%

(6) Load Limit: 10,000 g

(7) Calculation Input: Untensioned Diaper Circumference, Load Point at500 g, 1,000 g, 2,000 g, 3,000 g, 4,000 g, 5,000 g, 6,000 g

(8) Calculation Results Diaper Circumference at 0 g (=untensioned),extension at load point at 500 g, at 1,000 g, at 2,000 g, at 3,000 g, at4,000 g, at 5,000 g, at 6,000 g, at peak load, Load at Peak,circumference at peak load Diaper circumference at certain load point iscalculated as below

(Diaper Circumference)=(Untensioned Diaper Circumference)+(extension)×2

Extension at certain load point is calculated as below.

(Extension)=(Extended Diaper Circumference−Untensioned DiaperCircumference)/(Untensioned Diaper Circumference)

The test method is executed as below.

(1) Prepare sample diapers and measurement data

(2) Set up the Instron Loadcell and Jog following the Instron Settingabove then calibrate the Loadcell

(3) Log in to the TestWorks system

(4) Choose tensile test method from the method list tool bar, then letControl Panel, Load Meter, Extension Meter, and Handset show up on thescreen

(5) Enter the Untensioned Diaper Circumference data into gauge length inthe calculation input

(6) Set up the Gauge Length using a ruler following the Gauge LengthSetting described above

(Example: Untensioned Diaper Circumference=380 mm→GaugeLength=380/2-30=160 mm)

(7) Reset the Load in the Load Meter and Extension in the ExtensionMeter

(8) Measure the product weight by putting a product to be test on theupper bar then reset the load again

(9) Put the sample diaper on the Jog with checking the cuff/leg elasticdoes not stick on the bar

(10) After putting the diaper on the jog, do not reset the Load Meter

(11) Click the “Run” to start the measurement

(12) When the measurement has been done, the jog returns to the originalposition

(13) Click “File” to save the data and remove the diaper

(14) Repeat the step 6-13 for other sample

The data are evaluated as follows:

(1) After completion for all samples, export the data into anappropriate spreadsheet program (i.e. Microsoft Excel)

(2) “Force versus extension curve” is obtained by plotting the force ingrams against diaper extension in percent

(3) “Modulus of extensibility” is obtained by dividing the forcedifference between two successive data points by the extensiondifference between the two same points

(4) “Modulus of extensibility versus extension curve” is obtained byplotting the modulus of extensibility obtained in the step of (3)against diaper extension in percent

As stated above, the continuous belt zone 38 creates fit force in thepull-on diaper 20 when positioned on the wearer, to maintain the pull-ondiaper 20 on the wearer. The continuous belt zone 38 further includes azone of extensibility that comprises elastic materials such as the sideelastomeric material 124 and the waist elastomeric material 200. Thezone of extensibility can further include a leg elastomeric material.The leg elastomeric material comprises elastomeric material such as theelastic strands 64 as shown in FIG. 3. The leg elastomeric material cancomprise the material used for the side elastomeric material 124 or thewaist elastomeric material 200. Herein “zone of extensibility” refers toa continuous area or a continuous zone of the pull-on diaper renderedextensible by an elastomeric material having the form of a continuousplane layer with or without apertures, or the form of strands that arenot connected to each other. The zone of extensibility is that portionin the continuous belt zone 38 which substantially generates the skincontact pressure in the continuous belt zone 38. The skin contactpressure generated by the zone of extensibility contributes tomaintaining the pull-on diaper on the wearer (sustained fit of thepull-on diaper). The skin contact pressure in the zone of extensibilitycan not be uniform everywhere. For example, the skin contact pressure ofthe zone of extensibility between about the waist opening and about theleg openings can be different from each other. Additionally, the skincontact pressure can vary around the radial circumference of the diaperor the leg circumference of the diaper.

In the zone of extensibility, the elastic component of the elastomericmaterial (such as a plurality of first strands 125 and a plurality ofsecond strands 127 of the elastomeric scrim 124 shown in FIG. 6)pressing on the skin usually generates higher skin contact pressure thanthe remainder of the area of the zone of extensibility (such as aplurality of apertures 132 of the elastomeric scrim shown in FIG. 6).Therefore, lower skin contact pressure of the elastomeric materialpressing on the skin leads to a reduction of the local skin incidence.

The skin contact pressure of the elastomeric material (either the sideelastomeric material and/or the waist elastomeric material) pressing onthe skin should be not less than about 0.1 psi in order to maintain thepull-on diaper 20 on the wearer, preferably not less than about 0.2 psi,more preferably not less than about 0.3 psi. The skin contact pressureof the elastomeric material (either the side elastomeric material and/orthe waist elastomeric material) pressing on the skin should be notgreater than about 0.75 psi in order not to cause skin marking in thezone of extensibility, preferably not greater than about 0.65 psi, morepreferably not greater than about 0.55 psi. Any combination selectedfrom the above ranges of the skin contact pressure of the elastomericmaterial pressing on the skin is effective in providing a pull-on diaperwith a reduced risk of drooping, sagging or sliding down from theposition on the wearer, with a reduced risk of skin incidence in thezone of extensibility, and with a reduced risk of skin incidence by theelastomeric material. The skin contact pressure of the elastomericmaterial (leg elastomeric material) pressing on the skin should be notless than about 0.1 psi to maintain the pull-on diaper 20 on the wearer,preferably not less than about 0.2 psi, more preferably not less thanabout 0.3 psi. The skin contact pressure of the elastomeric material(leg elastomeric material) pressing on the skin should be not greaterthan about 0.75 psi not to cause the skin incidence in the zone ofextensibility, preferably not greater than about 0.65 psi, morepreferably not greater than about 0.55 psi. The method to obtain theskin contact pressure of the elastomeric material pressing on the skinis set forth below.

The skin contact pressure of the elastomeric material pressing on theskin within the zone of extensibility about the waist opening can behigher than the skin contact pressure of the elastomeric materialpressing on the skin at the remainder of the area within the zone of theextensibility to provide a sustained fit of the pull-on diaper about thewaist opening. The skin contact pressure of the elastomeric materielpressing on the skin within the zone of extensibility about the legopenings can be higher than the skin contact pressure of the elastomericmaterial pressing on the skin at the remainder of the area of the zoneof the extensibility to provide a sustained fit of the pull-on diaperabout the leg openings. The skin contact pressure of the elastomericmaterial pressing on the skin about the waist opening and about the legopenings within the zone of extensibility can be higher than the skincontact pressure of the elastomeric material pressing on the skin at theremainder of the area within the zone of the extensibility. Thedifference between the highest skin contact pressure of the elastomericmaterial pressing on the skin within the zone of extensibility and thelowest skin contact pressure of the elastomeric material pressing on theskin should be less than about 0.65 psi, preferably less than about 0.45psi, more preferably less than about 0.25 psi. As the difference becomescloser to zero, the skin contact pressure of the elastomeric materialpressing on the skin within the zone of extensibility becomes closer touniform everywhere. This further contributes to reduce a skin incidencewhich have caused by the different pressure.

The pull-on diaper 20 further comprises additional elastomeric materialsuch as the spacing means 58 of the inner barrier cuff 54. It ispreferable that these additional elastomeric materials incorporated inthe pull-on diaper 20 gives skin contact pressure of the additionalelastomeric material pressing on the skin of the wearer of not greaterthan about 0.75 psi. Preferably, the skin contact pressure of theadditional elastomeric material pressing on the skin of the wearer isnot greater than about 0.65 psi, more preferably not greater than about0.55 psi.

The method to measure the skin contact pressure of the elastomericmaterial pressing on the skin within the zone of extensibility is setforth below. The method entitled “AMI Air-pack Type Contact SurfacePressure Measurement System” is commercially supplied by AMI Co., Ltd.to measure the surface contacting pressure generated between softmaterials. This method is modified to measure the contacting pressurebetween the diaper and wearer's body. Air pressure indicated representsthe force of contact surface from which the force absorbed by ductilityof the material has been deducted. The sensing part is composed of anair pack made of a very soft thin film, of a tube introducing to themain unit and the measured value is converted into DC output (10 mV=1gf/cm²).

This test method requires sample preparation below.

(1) The sample diaper to be tested should be taken from the bag

(2) Measure the width of the actual elastomeric component of theelastomeric material (i.e. elastic strands) under the 50% stretchedcondition and calculate the percent area of the elastomeric component

This test method entitled “AMI Air-pack Type Contact Surface PressureMeasurement System” involves the following equipment below.

(1) Air-pack AMI Co., Ltd. Model Ø15 mm (2) Main Unit AMI Co., Ltd. AMI3037-2 (3) Option Unit AMI Co., Ltd. AMI 3037-2B (4) Air Cylinder AMICo., Ltd. (5) Calibration Set AMI Co., Ltd. (6) Data Collector ANRITSUMETER Co., Ltd. AM-7052 (7) Data Converting Software ANRITSU METER Co.,Ltd. DATA COLLECTOR System AMS7006WIN ver. 2.0 for Windows

This test equipment described above requires the setting below.

(1) Connect the output cable to the output connector of the main unitand connect the opposite side of the output cable to the data collector

(2) Turn on the power

(3) Use the gear, push the head of air cylinder to the end in theshortest length

(4) Connect the air pack to the air cylinder

(5) Insert the pin into the blue head on the gear, turn the gear untilthe pin comes to the end, wait 3 seconds

(6) Press the release lever for making air cylinder pressure to be thesame with and ambient pressure, wait 3 seconds

(7) Insert the pin into the hole of the gear whose color is the samewith the air pack, turn the gear until the pin comes to the end

(8) Remove the air pack from the air cylinder, turn the gear until thepin comes to the end

(9) Check if the output signal from the main unit is close to zero withallowance of 5 mV (0.5 gf/cm²)

(10) Connect the air pack to the main unit (connection should be made inone action. If you renew connection, inside volume of air pack must bechanged)

(11) Press the air pack by hand flat or finger for removing all the airfrom the air pack, check the output signal transmitted from the mainunit, be careful that this is the maximum measurement value and that thesystem can not measure any values exceeding the maximum measurementvalue. If the contact surface is bent too much, and if output signalfrom the main unit exceeds +20 mV (2 gf/cm²), connect the air cylinderand press the release lever

(12) Prepare at least 2 air-packs for standard measurement

This method utilizes a standard mannequin 350 having the form shown inFIGS. 9 and 10 and is modeled after the body shape in a sitting postureof a wearer. The shape and the dimension of the standard mannequin 350should be based on the body dimension data taken from the actual diaperusers. The standard mannequin 350 has an upper portion 352 and a lowerportion 354. The upper portion 352 and the lower portion 354 are dividedby the lower torso line 380. The lower torso line 380 is thecircumferential line through the upper portion of the pubic bone. Theupper portion 352 includes a torso portion 353. The torso portion 353has an upper surface 355 (shown in FIG. 11) surrounded by the waist line357 which is the circumference line about the top waist of the torsoportion 353. The torso portion 353 has a height defined by the heightbetween the waist line 357 and the lower torso line 380. Thecircumference of the torso portion 353 gradually increases from thewaistline 357 toward the lower torso line 380. The lower portion 354includes a hip portion 356 at the back of the lower portion 354, and theleg portions 358 protruding from the hip portion 356 at the front of thelower portion 354. The hip portion 356 and the leg portions 358 aredivided by the crotch crease line 359 along the fat fold at the front ofthe body. The two leg portions 358 have a crotch angle 362 that is theangle subtended between the inner thighs 364. The leg portion 358 has athigh line 366 that is the circumferential line about the thigh of theleg portion 358. The upper surface 355 has a shape surrounded by thewaistline 357 that comprises straight lines and curve lines. FIG. 11shows one preferred example of the shape of the upper surface 355, whichis determined, based on the actual wearer dimension. The standardmannequin is made of vinyl chloride.

The actual dimension of the standard mannequin for a diaper designed tofit the wearer weighing from about 7.0 kg to about 10.0 kg is shownbelow.

Circumference at the waistline: 460 mm Circumference at the lower torsoline: 470 mm Circumference at the crotch crease line: 310 mmCircumference at the thigh line: 275 mm Height of the torso:  75 mmCrotch angle: about 60 degrees

The actual dimension of the standard mannequin for a diaper designed tofit the wearer weighing from about 9.0 kg to about 14.0 kg is shownbelow.

Circumference at the waistline: 495 mm Circumference at the lower torsoline: 505 mm Circumference at the crotch crease line: 330 mmCircumference at the thigh line: 290 mm Height of the torso:  80 mmCrotch angle: about 60 degrees

The actual dimension of the standard mannequin for a diaper designed tofit the wearer weighing from about 13.0 kg or above is shown below.

Circumference at the waistline: 520 mm Circumference at the lower torsoline: 530 mm Circumference at the crotch crease line: 350 mmCircumference at the thigh line: 305 mm Height of the torso:  85 mmCrotch angle: about 60 degrees

The measurement points for the waist elastomeric material and the sideelastomeric material are determined as below.

Point P1 is the point of the minimum radius of the waist curvature lineat the right side of the torso portion. Point P2 is the point of theminimum radius of the waist curvature line at the left side of the torsoportion. Point P3 is the point at the center of the back of the torsoportion. Point P4 is the point at the center of the front of the torsoportion. The measurement points P1, P2, P3, and P4 should be mountedabout 10 mm below the waistline and should be fully covered by the waistmaterial of the sample diaper. Point P5 is the point at the front of theright leg portion and point P6 is the point at the front of the left legportion. The Air-packs for the measurement point P5 and P6 should bemounted right under the elastomeric material contacting the mannequin'sleg portion.

The measurement points for the leg elastomeric material are the pointswhere the elastomeric material presses on the skin of the standardmannequin.

This method is executed as below.

(1) Set up the pressure measurement system following the setting above

(2) Prepare sample diapers and mount the diaper on the standardmannequin

(3) Place two Air-packs at the point P1 and P2 and measure the pressure

(4) Record the pressure measurement data and check if the pressuresignal recovers close to zero with allowance of 5 mV (0.5 gf/cm²)

(5) Place two Air-packs at the point P3 and P4 and measure the pressure

(6) Record the pressure measurement data and check if the pressuresignal recovers close to zero with allowance of 5 mV (0.5 gf/cm²)

(7) Place two Air-packs at the point P5 and P6 and measure the pressure

(8) Record the pressure measurement data and check if the pressuresignal recovers close to zero with allowance of 5 mV (0.5 gf/cm²)

(9) Repeat the step 2 to 8 for 1 sample diaper

The data are evaluated as below.

(1) “Local average skin contact pressure within the zone ofextensibility” is obtained by converting the measured voltage into psi(10 mV=1 gm/cm²)

(2) “Skin contact pressure of the elastomeric material pressing on theskin” is then obtained in psi by dividing the “local average skincontact pressure within the zone of extensibility” obtained above by thepercent area of the elastomeric component.

The materials employed in making presently-commercially-availabledisposable diapers, pull-on diapers, and similar disposable absorbentarticles, generally have a coefficient of static friction on theirskin-facing surfaces of from about 0.15 to about 0.23. Coefficient ofstatic friction values at those relatively low levels facilitateapplication of the diaper to the body of the wearer, but they alsodictate relatively high skin contact pressures between the diaper innersurface and the body of the wearer, of the order of about 1 psi. Thatlevel of skin contact pressure is particularly advantageous in thewaistband area, to maintain the diaper in its preferred wearing positionfor optimum effectiveness. It is those relatively higher skin-contactpressures that lead to red marking of the skin of the wearer. Such skinred-marking can be both pressure-induced marking as well asabrasion-induced marking, the latter occurring when surfaces of thediaper move relative to the skin of the wearer as the wearer moves hisor her body.

In accordance with the present invention, reduction of the contactpressure of a disposable diaper against the skin of a wearer providesincreased wearer comfort. Additionally, reduction of the diaper-to-skincontact pressure also reduces pressure-induced and abrasion-induced redmarking of the skin of the wearer. However, excessive reduction of theskin contact pressure of the diaper, particularly in the waistband areaof the diaper, can result in slippage of the diaper on the wearer'sbody, with resultant undesirable drooping-or sagging of the diaper. Ithas been found that such undesirable consequences of contact pressurereduction can be overcome by increasing the coefficient of staticfriction at selected areas within the interior of the diaper. By“interior” is meant the surface of the diaper that contacts the skin ofthe wearer.

An increase in the coefficient of static friction of the skin-facingsurface of a disposable diaper can be selectively provided at strategicareas on interior, skin-facing surfaces of the diaper with beneficialresults. Referring to FIGS. 1 and 3, pull-on diaper 20 includes a pairof retention zones 400, 402 (only one of which is visible in FIG. 1),one on each side of the diaper, within the interior of the waistbandarea and at positions that substantially overlie the hipbone of thewearer when the diaper is worn. Retention zones 400, 402 can be providedby a material that has a higher coefficient of static friction than doesthe body-facing surface of topsheet 24, or the body-facing surface offront extensible ear 46, or the body-facing surface of back extensibleear 48, diaper inner surfaces that together define the major portion ofthe interior, body-facing surfaces of the diaper.

Positioning the retention zones at substantially the hip-contactingareas of the inner surfaces of waistband 57, 59 minimizes the skinabrasion effect of slippage forces that come into play when the wearerof the garment moves his body. In that regard, at the hip-contactingareas of the diaper there is less relative movement between the diaperinner surface and the skin of the wearer, as compared with some otherareas of the diaper, such as the stomach-contacting area, for example,where significant relative movement between the diaper and the wearercan occur. Additionally, because the hip-contacting surfaces of thediaper are generally the surfaces that are gripped and spread apart toenlarge the circumference of the waistband during application of thediaper, positioning the retention zones at those areas serves tominimize the contact of the retention zones with the skin of the weareras the garment is being applied to the body of the wearer. Thus, thehigher-friction, hip-contacting surfaces of the diaper are held awayfrom the wearer's body during application of the diaper, andconsequently a higher coefficient of static friction in those areas doesnot operate to impede application of the diaper.

In addition to the hip-contacting surfaces of the diaper, otherinterior, skin-facing surfaces of the diaper that can have a locallyhigher coefficient of static friction can include the back-contactingarea of waistband 59. A higher coefficient of static friction on thatsurface further improves the position-retention characteristics of thediaper, and thereby further minimizes the likelihood of downwardslippage of the diaper when in use. As shown in FIG. 3, such a backretention zone 404 can be provided on the inner surface of waistband 59as an elongated rectangular strip of a high coefficient of frictionmaterial. Alternatively, retention zone 404 can also be defined by aseries of narrow, spaced, substantially parallel strips, or by a seriesof spaced spots positioned along the inner surface of waistband 59 ofthe diaper. Advantageously, such a back retention zone 404 can beemployed in addition to hip-contacting retention zones 400, 402, ifdesired. However, the sizes and positioning of other higher coefficientof static friction surfaces within the interior of the diaper, and atpoints spaced from the hip-contacting surfaces, must be carefullyselected so that those non-hip-contacting surfaces do not unduly impedeapplication of the diaper.

Hip-contact-area retention zones 400, 402 preferably have as small anarea as possible, consistent with their diaper position retentionpurpose, to reduce the overall cost of the garment while still providingthe benefits of the present invention. In that regard, hip-arearetention zones 400, 402 can each have an aggregate area of from about0.01 in² to about 16 in² per side, preferably from about 0.25 in² toabout 10 in² per side, and most preferably from about 1 in² to about 3.5in² per side. And in addition to hip-contacting retention zones that areunitary, continuous areas having a relatively high coefficient of staticfriction, such as the generally rectangular form of retention zones 400,402 as shown in FIG. 1, the respective retention zones can alternativelybe provided in the form of several thin, substantially parallel strips(see FIG. 20), or in the form of closely spaced spots that can be of anyconvenient geometric form, such as circles, rectangles, ovals, and thelike, with intervening areas that do not exhibit a higher coefficient ofstatic friction.

When provided in the form of spaced spots, the total area over which thespots can be provided, whether in the hip-contacting areas or in thewaist-contacting areas, is preferably about 3.5 in² per side for thehip-contact areas, and preferably about 3.5 in² per waist-contact area,but the aggregate areas of the individual high coefficient of staticfriction spots should preferably be within the ranges specified above.As a further alternative, retention zones 400, 402 can be in the form ofone or more thin, elongated areas that have their major axessubstantially parallel with the transverse centerline of the diaper, orthey can be one or more thin, elongated areas that have their major axessubstantially parallel with the longitudinal centerline of the diaper.

Suitable ways of providing retention zones that can be employed toprovide the desired increased coefficient of friction can includecoatings or patches of relatively high coefficient of static frictionmaterials. Coatings can include, but are not limited to, coatings ofpressure-sensitive materials or of tacky materials. Patches can be inthe form of thin films, or the like, that are adhered to or otherwiseconnected with the interior surface of the waistband in either or boththe hip-contacting area and the rear waist area of the garment. Examplesof suitable coating materials are polymeric materials, such as hot meltresealable adhesives that are flexible when cooled; rubber-basedmaterials, including solid rubber and rubber-based foams; and any latexor hot melt material that has sufficient frictional properties to hold adiaper in position on the body of a wearer during use. Morespecifically, coatings made from the following materials are suitable:

ethylene vinyl acetate copolymers—could be applied as a hot melt or as awater based coating—the best candidates have at least 28% vinyl acetate;

polyvinyl acetate—normally used in water-based emulsions;

styrene-butadiene—applied in an emulsion or as a hot melt;

cellulose acetate butyrate—normally hot melt coatings;

ethyl cellulose—normally blended with a plasticizer and a resin andapplied as a hot melt;

acrylics-normally emulsion systems that are not blended;

synthetic rubber hot melt-Kraton® block copolymers having elastomericand styrenic blocks, rubber, resin, and plasticizer blends; and

other hot melts-polyethylenes (alone or blended), polyamides, and thelike.

Typical suitable coating compositions are the ethylene-vinyl acetatecopolymers, acrylic terpolymers of methacrylic acids, acryliccopolymers, ethylene-vinyl acetate/resin latex emulsions, ethylene-vinylacetate hot-melt adhesives, synthetic rubber (block copolymers withelastomeric and styrenic components) hot melt adhesives, and polyvinylacetate/resin emulsions. Such materials are available from H. B. FullerCompany, E. I. DuPont, and Findley Adhesives, among others, and havebeen used as hot-melt and water-based coatings for barrier coatings fornonwovens and/or papers. Those skilled in the art will appreciate thatother coating materials are also available for locally raising thecoefficient of static friction on interior surfaces of disposablediapers.

When applied as a coating, the materials are preferably applied in sucha manner as to provide a coating of substantially uniform thickness,overlying the innermost, skin-facing surface of a portion of the diaperwaistband, and having an area of the magnitude identified above.Additionally, from the standpoint of additional comfort to the wearer,the coatings employed to provide the retention zone of the presentinvention preferably are breathable or are made to be porous, such as byproviding a plurality of small, spaced apertures throughout the coatedretention zone.

High coefficient of static friction coating materials can be appliedusing a number of methods that are known to those skilled in the art.Methods for coating include, but are not limited to, extrusion coating,slot coating, gravure printing, and screen printing. Additionally, knownapplication methods can be employed to deposit in desired areasmaterials in loose fiber form that exhibit high coefficient of staticfriction properties. Examples of suitable materials include a meltblownor spunbond application of fibers of any of the fibrous polymericmaterials previously identified.

Coatings can be applied either at the raw material supplier's facility(i.e., the supplier of the nonwoven material contained within the diaperwaistband or side panels) or they can be applied on-line duringmanufacture of the diaper.

Coatings can also be applied either before or after activation of theelastic laminate material forming part of the waistband or the sidepanel structure.

Retention zones 400, 402 can be provided in the form of patches that areseparately formed and thereafter suitably secured to the interiorwaistband or side panels of the diaper. When applied as patches, theretention zones can be made from a number of different materials thatare thin, flexible, and that can be adhered or otherwise firmly attachedto the innermost, skin-facing surface of the diaper waistband or sidepanels. Examples of materials from which such patches can be made arepolymeric films, such as polyvinylidene chloride, apertured polymericfilms, fibrous nonwoven sheets, scrims, scrim nettings, or fibrousflocked substrates, either with or without the addition of surface-basedtackifier materials for enhancing the coefficient of static friction ofthe underlying base material. The patches are preferably porous orbreathable, and they can be formed from porous films of the typedisclosed in U.S. Pat. No. 3,989,867, entitled “Absorptive DevicesHaving Porous Backsheet,” which issued on Nov. 2, 1976, to Sisson, thedisclosure of which is hereby incorporated by reference to the sameextent as if fully rewritten.

A patch formed from a nonwoven web can be any rubbery compositioncontaining elastomeric components such as natural rubber andisobutylene, polymerized or blended with other polymers that areprovided to control the degradation, melting point and flexibility ofthe elastomers. The nonwoven web can include microfibers including atleast about ten percent (10%) by weight of an A—B—A′ block copolymer,where A and A′ are each a thermoplastic end block that includes astyrenic moiety, and where B is an elastomeric poly(ethylene-butylene)midblock, and from greater than zero percent (0%) by weight, up to aboutninety percent (90%) by weight, of a polyolefin, which, when blendedwith the A—B—A′ block copolymer and subjected to a combination ofelevated temperature and elevated pressure conditions, is adapted to beextruded, in blended form, with the A—B—A′ block copolymer. Thepolyolefin material can be selected from the group consisting ofpolyethylene, polypropylene, polybutene, ethylene copolymers, propylenecopolymers, butane copolymers, and blends of at least two of thosematerials. U.S. Pat. Nos. 4,663,220, 4,692,371, 4,741,949, 4,789,699,and 4,803,117 describe extrudable compositions and methods of formingsuch compositions, especially elastomeric nonwoven webs, and thedisclosures of those patents are hereby incorporated by reference to thesame extent as if fully rewritten.

Further, a patch of nonwoven material can include A—B—A′ blockcopolymers with polybutadiene or polyacetate midblocks and polystyreneend blocks, polystyrene/polyethylenebutylene/polystyrene block copolymerresins, and blends of such resins with materials to control theirflexibility and degradation. It should be noted that such compositionsshould be readably extrudable and should be capable of easily beingformed into fibrous webs.

In providing the retention zones described herein, the highercoefficient of static friction at those zones of the garment ispreferably of the order of at least about 500% greater than thecoefficient of friction of the major portion of the body-facing surfacesof the diaper. Included within those body-facing surfaces is topsheet 24and the major portions of the elastically extensible side panels, suchas the body-facing surface of front extensible ear 46 and thebody-facing surface of back extensible ear 48, each defining a portionof the interior, skin-facing surface of the diaper. Advantageously, thehigher coefficient of static friction at the retention zones can rangefrom greater than about 0.3 to about 4.0, preferably from about 0.4 toabout 2.0, and most preferably from about 0.7 to about 1.5. When suchretention zones are provided in such a garment, the waistband hoopstress that is necessary to maintain the garment in substantially itsinitially-applied position on the body of the wearer can be reducedsignificantly. In that regard, the usual range of pressure of thegarment inner surface against the skin of the wearer for maintainingdisposable, pull-on absorptive garments in the desired position on thebody of the wearer is from about 0.05 psi to about 0.8 psi. At thehigher of those pressure levels some wearers, because of their body sizerelative to the size of the diaper, cari exhibit red markings about thewaist area because of the tightness with which the waistband grips thewearer's body.

By providing at the inner, skin-facing areas of the waistband retentionzones having a higher coefficient of static friction, the hoop stress ofthe waistband, and consequently the pressure it exerts against the skin,can be reduced. The higher friction surfaces that are provided permitthe diaper to be retained in substantially its initial, as-appliedposition, without significant red marking, and even though the weight ofthe diaper may have been increased by the absorption of body wastematerials.

The coefficient of static friction values given herein are based on atest procedure that utilizes a Heidon 14DR surface property tester. Thetesting was carried out at 25° C., 50% relative humidity, and a standard400 file polish (JIS) steel plate was used as the substrate againstwhich the material whose stapic coefficient of friction was to be testedwas placed. The sample material was attached to a 30 mm×30 mm indenterso that it completely covered one of its major surfaces. If the materialto be tested was stretchable, the test was conducted with the directionof stretchability arranged perpendicular to the direction of travel ofthe moving base of the Heidon 14DR tester. A single travel mode wasemployed with a travel speed of 600 mm/min. Various normal loads wereapplied and the coefficient of static friction was determined betweenthe sample mounted on the indenter and the standard steel plate usingthe supplier-furnished analysis program.

An exemplary way in which a patch of material having an increasedcoefficient of static friction can be achieved is to provide a thermallybonded laminate of two distinct materials. One of the materials can havesufficient body for ease of handling, and the other of which might bemore difficult to handle alone but that has a relatively highcoefficient of static friction. Such a high coefficient of staticfriction material can be an elastomeric scrim in the form of an elasticnetting material, such as that identified and described earlier hereinas elastomeric scrim 124, the structure of which is illustrated in FIG.6. Elastomeric scrims typically have a relatively high coefficient ofstatic friction, of the order of about 3.0. One such elastomeric scrimmaterial is available from Conwed Plastics Company, of Minneapolis,Minn., and is identified as XO2514. The Conwed elastomeric scrimmaterial is a netting made from a styrene-butadiene-styrene triblockcopolymer material. The scrim is in the form of a plurality of spaced,substantially parallel first strands, and a plurality of spaced,substantially parallel second strands, wherein the first and secondstrands are disposed at substantially right angles to each other.Further, the first strands and the second strands are joined together todefine a coherent elastomeric web that includes a plurality ofsubstantially rectangular open areas that are bounded and defined byrespective interconnected first and second strands. The Conwed scrim hasa thickness of from about 0.5 to about 1.5 mm, an open area of about80%, a basis weight of about 120 gsm, and conforms with theextensibility properties hereinbefore described for side elastomericmaterial 124.

The elastomeric scrim is in the form of a thin, very flexible sheet thatbecause of its flexibility is difficult to handle by itself underhigh-speed production conditions. Accordingly, the elastomeric scrimpreferably is joined with a less flexible sheet of base material toprovide a patch that is easy to handle, that has the desired elasticproperties, and that has on one face thereof the desired highcoefficient of static friction. A suitable base material should also beextensible, at least in one direction, so that it can stretch along withthe elastomeric scrim with which it is joined, and thereby conformitself with the contour of the body surface about which the patch isadapted to be brought into contact. A suitable nonwoven material for usein the patch laminate is available from Nisseki Corp., of Japan, and isidentified by the trade name “MD MIL1FE.” The nonwoven MIL1FE materialhas a basis weight of 20 gsm and is made from polyester (PET) fibersusing a spunbond process that provides a highlymachine-direction-oriented fibrous web that has an ultimate elongationin the cross-machine direction of greater than 200%.

A high-static-coefficient-of-friction patch can be formed by joiningtogether the scrim and the base nonwoven material by using apparatussuch as that shown generally in FIG. 15. A scrim 500 is superposed overthe surface of a nonwoven sheet 502, and the scrim and nonwoven areplaced between a pair of opposed, flat, heated press plates 506, 508.Scrim 500 is caused to be pressed into and to be bonded to surface 504of nonwoven sheet 502 by plates 506, 508, until the scrim is permanentlyattached to and embedded within the surface of the nonwoven.

The several steps in the lamination process for forming the patch areshown in FIGS. 16 through 18. The opposed, flat surfaces of plates 506,508 are initially spaced from each other, as shown in FIG. 16, and areheated to a temperature of the order of about 90 to about 100° C., whichis sufficiently low so as not to melt the higher-melt-temperature PETfibers of nonwoven 502, but to maintain the fibers of the nonwoven in anintact state, and is sufficiently high to soften scrim 500 sufficientlyto become tacky so that it can be pressed into the surface of and toadhere to the nonwoven. Scrim 500 and nonwoven 502 are placed betweenplates 506, 508 while in superposed relationship to each other.

As shown in FIG. 17, plates 506, 508 are brought toward each other topress scrim 500 and nonwoven 502 into closely contacting relationship.The contact pressure, the plate temperature, and the dwell time areselected to cause the scrim to soften sufficiently to be capable ofbeing pressed into the surface of the nonwoven and to be at leastpartially embedded therein. Plates 506, 508 are then withdrawn, as shownin FIG. 18, and the laminated scrim and nonwoven composite 510 can beremoved and allowed to cool for use. As shown in FIG. 18, one surface ofcomposite 510 includes embedded scrim material, with a portion of thescrim component extending slightly above the surface of the nonwovencomponent. The coefficient of static friction of the surface of thecomposite 510 into which the scrim is embedded is from about 2.8 toabout 3.0.

Composite 510 can be incorporated into a disposable, pull-on, absorbentpant article as waistband zone 37 shown as a part of disposable pantarticle 20 illustrated in FIG. 1. The composite imparts to article 20the increased slip resistance that provides improved performance of thearticle in terms of greater retention of the article in the preferredwearing position on the body of a wearer.

FIG. 19 is a cross-sectional view taken through waistband zone 37 andshows a preferred structural arrangement thereof. The outermost layer ofwaistband zone 37 is defined by a backsheet layer 520 of nonwovenmaterial (such as Fiberweb HEC nonwoven). Positioned inwardly ofbacksheet layer 520 is an intermediate layer 522 of nonwoven material(such as MILIFE nonwoven), and positioned inwardly of intermediate layer522 is a belt-like layer of composite 510 that has itshigh-static-coefficient-of-friction surface facing the body of a wearer.

Selected body-facing portions of waistband 37 that contact the stomachand the back of a wearer, and that are positioned above the areas atwhich absorbent core 25 terminates, can be provided by a material havinga relatively low coefficient of static friction. In that regard,rectangular layers 524 of consolidated nonwoven material (such asFiberWeb's DAPP) in strip form can be provided in overlying coveringrelationship to portions of composite layer 510 at the back and stomachportions of waistband 37. Layers 524 can be adhered to the waistband bysuitable adhesives of the type hereinbefore described, in order topermit to be exposed to the skin of the wearer only those portions ofwaistband 37 that are positioned above the side panels of the articleand that overlie the hips of the wearer. As a result, and as shown inFIG. 20, the hip-contacting portions of waistband 37 include compositelayer 510 containing an exposed scrim material that has a highercoefficient of static friction to provide the desired resistance toslippage.

Use of the waistband structure shown in FIGS. 19 and 20 enables areduction of the hoop stress that is normally generated within thewaistband when the garment is worn. The increased slip resistanceprovided by the preferred waistband structure does not require the samedegree of tension within the waistband to retain the absorbent articlein its desired wearing position for most effective functioning. Toprovide the benefits of the present invention, the portions of theoverall circumference of waistband 37 that include retention zones canbe up to about 100%, preferably from about 10% to about 60% and mostpreferably from about 25% to about 35%, preferably at eachhip-contacting portion of waistband 37. The foregoing percentages arefor a waistband when it is in its relaxed, unextended condition beforethe garment is applied to the wearer.

If desired, in addition to or instead of providing retention zones inthe waistband zone of a disposable absorbent article to improve articleretention when worn, the ears or side panels of the structure can beprovided with retention zones to provide increased resistance toslippage of the garment. In that connection, the same high coefficientof static friction laminate described above in the context of it use inthe waistband zone of the garment can be employed to form at least aportion of the area of the ear or side panel elements. For, example, andreferring to FIG. 20, the interior, skin-facing surfaces of ears 46, 48on each side of the diaper illustrated can include one or more areasthat are defined by a high-static-coefficient-of-friction composite 510having the structure hereinbefore described. The larger skin contactarea of those elements of the diaper structure provide larger-arearetention zones, to assist in maintaining the diaper in its preferredwearing position and in reducing the tendency for the diaper to slipdownwardly relative to the body of the wearer. In that regard, theaggregate skin contact area of such retention zones on ears 46, 48 onboth sides of the diaper can be up to about 13 in², preferably fromabout 3.5 in² to about 11 in², and most preferably from about 5 in toabout 6.5 in².

Because of the potentially greater skin contact area at the ears of thediaper, as compared with that at the waistband area, it is possible touse in the ear panels materials having a somewhat lower coefficient ofstatic friction than that of composite material 510 hereinbeforedescribed. In that regard, the coefficient of static friction can beselected based upon the areas of the retention zones—the larger the skincontact area the lower the coefficient of static friction of thematerial needed to obtain substantially the same retention force, orslip resistance. Thus, a panel can be provided having a somewhat lowercoefficient of static friction than that of exposed elastomeric scrim. Abase nonwoven material, such as HEC, a high elongation carded nonwovenavailable from FiberWeb Corp., of Simpsonville, S.C., is joined with alayer of a blend of EVA and Kraton melt-blown fibers, by thermalcalendaring, for example. The surface defined by the fibers has acoefficient of static friction of about 0.7, which is in excess of twicethat of commercially available nonwoven materials. Panels so formed canbe employed as the skin-facing surfaces of the side panels of anabsorbent article, such as ear panels 10, 11 of the article shown inFIG. 2. Preferably, the area of such high-coefficient-of-frictionretention zones included in the side panels is up to about 13 in², morepreferably from about 3.5 in² to about 11 in², and most preferably fromabout 5 in² to about 6.5 in².

Retention zones that provide a diaper-to-skin slip resistance of about1500 gm will generally be effective to prevent excessive sagging ordrooping of the diaper, while also minimizing the tendency for redmarking of the wearer's skin. Preferably the slip resistance is at leastabout 1000 gm, more preferably at least about 1500 gm, and mostpreferably about 2100 gm.

The slip resistance of a disposable diaper can be measured by providinga mannequin-type waist profile having the cross section shown in FIG.11, but without the leg members. The profile has a height of 110 mm anda circumference of 492 mm and is formed from styrofoam. A material isapplied to the exterior surface of the mannequin to simulate human skin.The preferred material is a product called BIOSKIN, which is apolyurethane material that can be obtained from Beaulax Company, ofJapan, and can be attached to the mannequin by an adhesive such asCemedine EP002, available from Cemedine KK, Tokyo, Japan. The BIOSKINmaterial has the following physical properties:

Dimensions 195 mm × 130 mm × 5 mm Rigidity 0 ˜ 5 Shore A @25° C. TowStrength 18 ˜ 20 kg/cm² @23° C. Tear Strength 3 ˜ 5 kg/cm² or more @23°C. Grow Range 450 ˜ 500% Transform Temperature 90° C.

In carrying out the slip resistance test procedure, a hole was drilledthrough the center of the mannequin, which was then mounted on a standand connected with one plate of an Instron tester. The diaper was thenconnected with the Instron load cell, and was then mounted in wearingposition on the mannequin. The diaper was allowed to relax on themannequin for a period of 5 minutes. The load cell was programmed tomove upward axially relative to the mannequin at 20 cm per minute andthe load (gmf) as a function of displacement (cm) was noted. The peakload (gmf) was determined for various commercially available diapers.The slip resistance is the peak load (gmf) for that diaper at thatcircumference. The product wearing force (for a waist circumference of492 mm) for each of the products was determined, and the product wearingforce and the slip resistance were used to determine the normalizedproduct slip resistance.

In addition to providing retention zones having a significantly highercoefficient of static friction than the usual skin-contacting materialsthat are included in presently-commercially-available disposableabsorbent articles, the present invention also contemplates theprovision of slip zones having a lower coefficient of static friction atselected skin-contacting areas of such structures. Providing such slipzones, or reduced friction zones, having a coefficient of staticfriction of less than about 0.2 facilitates the application and removalof such articles from the body of a wearer. In that regard, andreferring to FIG. 2, the zones of such articles that generally providerelatively high resistance to easy application and removal of thearticles include leg edges 153, 156, and 158, front waistband area 6,and the interior surfaces of the garment adjacent the leg openings, suchas leg flap panels 4. Reduction of the coefficient of static friction inthose areas to a level of less than about 0.15 can significantly reducethe drag forces that are experienced at specific areas of the body of awearer, such as the front waist area and the thigh areas enclosed by thediaper leg openings, where because of the elastic properties at the legcuffs and at the leg openings a relatively high pressure of the diaperstructure against the skin or high abrasion forces on the skin can beexperienced during application and removal of such garments. Suitablematerials to provide such a reduced coefficient of friction includematerials in patch form, such as silk, and sheet materials includingmeltblown or spunbonded fibers made from polyethylene.

As a further benefit, in addition to facilitating the application andremoval of a disposable absorbent article, the selective provision onskin-contacting surfaces of the article of relatively high andrelatively low coefficient of static friction zones can also improve thecomfort and the functionality of the article during the time it is worn.Thus, providing slip zones at skin-contacting areas of the article thatmove relative to the wearer's skin during the course of bodily movementsof the wearer can reduce skin abrasion and resultant red marking. Suchhigh relative motion zones include the front waist portion of thearticle, more specifically the area that overlies the stomach of thewearer, and also the edges of the leg cuffs, where it is advantageous toprovide low coefficient of static friction surfaces. Higher coefficientof static friction surfaces can be provided at the low relative motionzones of the article, such as at the leg crease, the hip-contactingsides, and the crotch crease, to aid in retaining the article inposition for optimum functionality. By strategically providing highcoefficient of static friction surfaces at the low relative motion zonesand low coefficient of static friction surfaces at the high relativemotion zones, the article can, in effect, be made to be self adjusting,relative to the wearer's body during wearing, to maintain the article inits preferred position on the wearer's body, to minimize skin abrasion,and to provide a greater degree of control over both the fit of thearticle and the positioning during wearing of critical functionalelements of the article, such as the absorbent core and the leg cuffs.

In addition to retention zones provided in the form of patches ofmaterials having a relatively high coefficient of static friction, thepresent invention includes the provision of a retention zone in the formof an inner band 450 of retention material such as is shown in FIGS. 12and 13. Band 450 can be an elongated, generally rectangular panel, asshown, having an outer face 452 adapted to face the wearer and tocontact the wearer's skin, and an inner face 454 that faces toward theinner surface 456 of waistband 458. A portion of inner face 454 issecured to the interior surface of waistband 458 of the diaper along aseam area 460. The seam area can define a connection between band 450and waistband 458 that can be effected by an adhesive, by heat sealing,or by other known connection means that are known to those skilled inthe art.

Band 450 can be a thin, flexible sheet of soft, non-irritating material,such as a polymeric sheet, a nonwoven sheet, or the like. Preferably,the band material is made from the patch material previously describedthat includes a nonwoven base member and a scrim that is impressed intothe surface of the nonwoven. The unattached portion of band 450 definesa flap 462 that can pivot about the lowermost edge 464 of seam area 460.

Outer face 452 of band 450 preferably has a relatively low coefficientof static friction, of the order of from about 0.2 to about 0.3, so thatwhen the diaper is pulled over the legs of the wearer and onto his lowertorso the low coefficient of friction enables application of the diaperto be effected without excessive resistance to sliding movement of theinterior surface of the diaper waist relative to the wearer's skin. Sucha relatively low coefficient of static friction can be obtained byappropriate selection of the band material, or it can be obtained byapplying a suitable low friction surface over the outer face of theband. Examples of suitable low friction surfaces include silk, a layerof spunbonded polyethylene fibers, or a high elongation carded nonwovensuch a HEC, available from FiberWeb corp., of Simpsonville, S.C.

Although outer face 452 has a relatively low coefficient of staticfriction, inner face 454 preferably has a relatively high coefficient ofstatic friction. The relatively high coefficient of static friction isdesirable because if the diaper slips downwardly relative to the body ofthe wearer, the limited frictional force resulting from the slidingmovement of band 450 against the wearer's skin will cause flap 462 topivot about edge 464, so that edge 464 will, in effect, as a hinge or apivot axis. Accordingly, as the diaper begins to slip downwardly fromits initial, as-applied position, the pivoting of flap 462 about edge464 will cause inner face 454 of flap 462 to come into contact with thewearer's skin. Accordingly, a relatively high coefficient of staticfriction is provided on inner face 454 so that additional downwardmovement of the diaper from its initial position is impeded. In thatregard, the preferred range of coefficient of static friction of innerface 454 is from about 0.3 to about 4.0, more preferably from about 0.4to about 2.0, and most preferably from about 0.7 to about 1.5. Thepreferred coefficient of static friction of outer face 452 is less thanabout 0.2, more preferably less than about 0.15. It will thus beapparent that band 450 serves simultaneously as an aid to application ofdiaper 20 as well as an aid to retention of diaper 20 after it has beenplaced in its preferred wearing position.

The benefits of the present invention involving the provision of astay-up disposable absorbent article, such as a disposable diaper, canalso be achieved without the addition of special materials in patch orcoating form. Thus, a disposable diaper having discrete areas of highercoefficient of static friction material can also be provided in astructural arrangement that is integral with the overall diaperstructure, one that does not require the addition of special, separateand distinct higher-coefficient-of-static-friction materials. In thatregard, the basic waistband structure hereinbefore described in thecontext of a disposable diaper can be modified so that elastic materialthat is positioned interiorly within the waistband of the diaper isselectively exposed. Elastic materials commonly included in suchwaistband structures typically have a higher coefficient of staticfriction than that of other materials defining the inner, body-facingsurfaces of a diaper. The elastic material is caused to be exposed andto come into direct contact with the skin of the wearer at selectedtimes, and when needed or desired to retain the diaper in its preferredwearing position.

One form of such a modified waistband structure is shown in FIG. 21.Waistband 600 is a continuous circumferential structure that has anouter surface layer 602 that faces away from the body of the wearer andan inner surface layer 604 that faces the body of the wearer. Layers 602and 604 are separated from each other by and are bonded to at least oneintermediate layer 606 that either constitutes or includes a layer of anelastic material having a higher static coefficient of friction thanthat of inner surface layer 604. The bonding together of the respectivelayers of the waistband structure can be effected by suitable adhesivesthat can be one of the adhesives hereinbefore described, or,alternatively, by thermal bonding or by other suitable bondingarrangements.

The modified waistband structure includes an inner surface layer 604that has a plurality of substantially linear notches 608 that extendupwardly from the lowermost edge 610 of inner layer 604 and thatterminate between lowermost edge 610 and uppermost edge 612. Notches 608can be in the form of cuts or slits that extend completely through innerlayer 604, and they can be located at predetermined circumferentialpositions around the inner circumference of waistband 600. The areas ofinner layer 604 between pairs of adjacent notches 608 are not fullybonded to the elastic material of intermediate layer 606, but areinstead permitted to hang loosely, as shown in exaggerated form in FIG.22. Unbonded portions 613 of inner layer 604 between a pair of spacednotches 608 define respective pivotable cover flaps 614 that overlie andcover adjacent, underlying areas 615 of elastic material in intermediatelayer 606 when the cover flaps are in the position shown in FIG. 22.

Cover flaps 614 can be caused to be pivoted or lifted to expose areas615 of elastic material of intermediate layer 606 as the diaper beginsto slip down from its initially-applied, preferred wearing position. Thepivoting or lifting of the flaps relative to intermediate layer 606 iseffected during downward movement of the waistband 600 relative to thebody of the wearer, which results in a pulling force on cover flaps 614that causes the flaps to pivot about a pivot line 616 that can bedefined by the lowermost edge of the bonded area between inner layer 604and intermediate layer 606.

After the diaper has moved downwardly along the body of the wearer asufficient distance, cover flap 614 has pivoted about pivot line 616 touncover area 615 of elastic material and to expose it to the skin of thewearer. The exposed elastic material, which either constitutes or formsa part of intermediate layer 606, has a significantly higher coefficientof static friction than that of the body-facing surface of inner layer604, of the order of at least about 1.5, preferably about 2.0 or more.When the elastic material comes into contact with the skin of the wearerthe frictional resistive force that results from the contact of theexposed area of elastic material with the skin of the wearer serves toresist further downward movement of the diaper and to retain the diaperin a position for effective functioning.

The unbonded areas in the form of cover flaps 614 can be positioned atthe hip-contacting portions of the waistband to define hip-contactingcover flaps on one or both opposed inner surfaces at each side of thediaper structure. Further, one or more unbonded areas in the form ofback-contacting cover flaps can be provided adjacent the portion of thediaper waistband structure that contacts the back of the wearer, eitherin addition to the hip-contacting cover flaps or instead of thehip-contacting cover flaps. The individual cover flaps can be aplurality of adjacent or spaced cover flaps each having acircumferential length of from about 0.5 in to about 12 in, preferablyfrom about 1 in to about 2 in, or they can be relatively large, unitarycircumferential cover flaps. In that regard, the cover flaps canencompass about 75% of the waistband inner circumference, preferablyabout 50%, and most preferably about 20%. If plural, relatively shortcircumferential length cover flaps are provided, preferably theindividual flaps have a circumferential length of from about 0.1 in toabout 5 in, more preferably from about 0.25 in to about 3 in, and mostpreferably from about 0.5 in to about 1 in.

The structure of a waistband incorporating one or more pivotable,discrete cover flaps can be as shown in FIGS. 21 and 22. Inner layer 604and outer layer 602 of waistband material can each be a. nonwovenmaterial of the character of those hereinbefore described. The elasticmaterial forming part of the intermediate layer 606 between the innerand outer layers 602, 604 can be an elastic scrim, such as theelastomeric scrims hereinbefore described and shown in FIGS. 6 and 15.Further, the elastic material can be in the form of a plurality ofcircumferentially-disposed bands. And instead of utilizing the elasticwaistband material as the high coefficient of static friction material,the higher static coefficient of friction materials hereinbeforeidentified can be employed instead, if desired.

Instead of or in addition to one more unitary, circumferentially spacedpivotable flaps, a plurality of smaller flaps can be provided. As shownin FIG. 22a, inner surface layer 604 can include a plurality of flaps618, wherein each of flaps 618 has a smaller flap dimension in thedirection parallel to longitudinal centerline 100 of the diaperstructure (see FIG. 3). The smaller flap structure shown in FIG. 22aprovides diaper position retention benefits similar to those obtainedwith the unitary, larger flap shown in FIG. 22, but because of thesmaller flap dimension it does so for smaller downward slippage of thediaper relative to the body of the wearer. Thus, by reducing flapdimension h shown in FIG. 22a, the retention feature comes into playmore quickly when diaper downward slippage begins.

As a further structural alternative, the elastic material in the diaperwaistband can be in the form of a porous, macroscopically-expanded,three-dimensional elastomeric web 630 as shown in FIG. 23. Elastomericweb 630 has a discontinuous outer surface 632 and a discontinuous innersurface 634 that are spaced from each other to define theoutwardly-facing surfaces of the web. Preferably, web 630 is a formedfilm, and it can include at least two polymeric layers, with at leastone of the layers being an outer elastomeric layer 636 and at least oneof the other layers being a substantially less elastomeric inner layer638.

Elastomeric web 630 includes a multiplicity of apertures 640 in outersurface 632. Apertures 640 lie in the plane of outer surface 632 and arebounded by a continuous network of interconnecting members 642. Eachinterconnecting member 642 defines an inwardly-diverging cross-sectionalong its length from outer surface 632 to inner surface 634.Interconnecting members 642 terminate at inner surface 634 to defineinner apertures 644 that lie in the plane of inner surface 634 of web630. The detail of such an elastomeric web structure and a method bywhich it can be manufactured is disclosed in U.S. patent applicationSer. No. 08/816,106, filed Mar. 14, 1997, the disclosure of which ishereby incorporated by reference to the same extent as if fullyrewritten. A preferred porous elastomeric material is available fromTredegar Industries, Inc., of Richmond, Va., under the designationX-25007.

The outer apertures 640 can have any desired shape. Preferably, however,outer apertures 640 have a shape that includes a major axis and a minoraxis that are perpendicular to each other, such as an oval or ellipticalshape. Preferably, the major axis is oriented generally orthogonal tostrain induced stresses that are applied to the elastomeric web duringthe time the diaper is worn.

A further variant of a diaper waistband structure in accordance with thepresent invention is shown in FIGS. 23a and 23 b. Each of those drawingfigures shows a modified waistband inner layer 604 a that defines thebody-facing surface of the waistband and that overlies a material havinga relatively high coefficient of static friction. Layer 604 a can bemade from an extensible material, such as a nonwoven material of a typehereinbefore identified, but instead of a continuous, unbroken structureextensible layer 604 a includes a plurality of relatively short,substantially linear cuts or slits 650 that are spaced from each otherand that extend completely through the material defining layer 604 a.

As shown in FIG. 23a, slots 650 extend in the direction of longitudinalcenterline 100 (see FIG. 3) of the diaper structure. A plurality ofspaced, substantially parallel rows 652 of generally aligned slits 650are provided, with the slits in adjacent rows 652 longitudinally offsetfrom each other. As a result, when layer 604 a is placed under tensionin a direction transverse to longitudinal centerline 100, whichcorresponds with the circumferential direction of the waistband on adiaper, the edges of slits 650 will separate from each other to define aplurality of spaced openings 654. Thus, when openings are formed inlayer 604 a the underlying layer of relatively high coefficient ofstatic friction material will be partially exposed to the skin of thewearer, thereby providing the desired resistance to downward slippage ofthe diaper when it is worn. As shown in exaggerated form in FIG. 23b,openings 654 will assume substantially a diamond shape, with the area ofeach opening dependent upon the lengths of the slits, the extensibilityof the material, and the tensile stress (represented by double-headedarrow 656) that is imposed on layer 604 a. Slits 650 can have a lengthof from about 2 mm to about 5 mm, preferably from about 2 mm to about 3mm, and a longitudinal spacing between adjacent slits in a given row offrom about 2 mm to about 5 mm. Further, the lateral spacing betweenadjacent rows 652 of slits can be of the order of from about 2 mm toabout 5 mm. The slits can be provide by passing a sheet of the materialthrough a rotary cutter apparatus of a type known to those skilled inthe art.

Layer 604 a can be adhesively secured to an underlying layer of elasticmaterial, such as an elastomeric scrim having a relatively highcoefficient of static friction, that is exposed upon the formation ofopenings 654. Alternatively, a layer of adhesive that is utilized tosecure layer 604 a to an underlying structural layer of waistbandmaterial can also be the relatively high coefficient of static frictionmaterial, which when placed under tension will expose the adhesivematerial upon formation in layer 604 a of openings 654. The adhesive canbe sprayed on an underlying layer of material, or it can be applied in apattern of adhesive-containing areas and non-adhesive-containing areas,such as a spiral pattern, or the like.

In addition to providing one or more discrete zones having one or morepivotable flaps to cover and uncover a scrim that defines a zone havinga high coefficient of static friction, permanently exposed areas ofscrim can also be provided, if desired. In that case one or moreportions of the inner circumference of the waistband is covered by asuitable covering material, such as a nonwoven of the type describedherein, with intervening areas of exposed scrim of substantially uniformcoefficient of static friction that extend over predetermined areas ofthe skin-facing surface of the waistband.

If the high coefficient of static friction areas are provided by amaterial that overlies a base material, such as a nonwoven, thatmaterial can be applied in such a way as to vary the coefficient ofstatic friction from a relatively high value to a lower value over agiven area. Thus, material that is added to the interior surface of thediaper can be applied in a denser pattern at. predetermined areas toprovide a high coefficient of static friction, and can the density ofthe applied material can diminish in a circumferential direction of thewaistband, so that the coefficient of static friction varies overpredetermined areas from a relatively high coefficient of staticfriction to a relatively low value. More specifically, when thecoefficient of static friction of a portion of the interior surface ofthe diaper is increased by laying fibers of meltblown material, thedensity of the fiber application can be gradually varied from a highfiber density that provides a high coefficient of static friction, to alower fiber density so that the coefficient of static frictiondiminishes substantially uniformly.

Alternatively, instead of a gradual variation of coefficient of staticfriction, the friction-increasing material can be applied at particulardensities in discrete areas on the interior surface of the diaper toprovide zones of high coefficient of static friction, intermediatecoefficient of static friction, and low coefficient of static friction.Each of those areas can have a relatively uniform coefficient of staticfriction value within the area of a given zone, or the coefficient ofstatic friction values can vary gradually. As shown in FIG. 24,waistband 37 of pull-on diaper 20 b includes a high coefficient ofstatic friction zone 550 at the opposed, hip-contacting areas of thewaistband. Zones 550 have an area as hereinbefore defined and have acoefficient of static friction of from about 1.5 to about 3.0. Waistband37 also includes one or more intermediate level coefficient of staticfriction zones 552 each having a area of from about 1 in² to about 4in², and having a coefficient of static friction of from about 0.2 toabout 1.5, and at least one low coefficient of static friction zone 554having an area of from about 1 in² to about 4 in², and having acoefficient of static friction of from about 0.05 to about 0.20. Asshown in FIG. 24, high coefficient of static friction zones 550 can beprovided at each of the side, hip-contacting portions of waistband 37 ofthe diaper, and optionally also at the back-contacting portion of thewaistband. Low coefficient of static friction zone 554 canadvantageously be provided at the stomach-contacting portion of thewaistband, which generally undergoes more relative movement over thewearer's skin than do the hip- and back-contacting areas. Intermediatecoefficient of static friction zones 552 can be provided between highcoefficient of static friction zones 550 at the hips and at the back,and also between high coefficient of static friction zones 550 at thehip-contacting areas and a low coefficient of static friction zone 554at the stomach-contacting area. Thus, the interior surface of waistband37 shown in FIG. 24 can have plural discrete zones that have differentcoefficients of static friction to provide a circumferential variationin waistband coefficient of static friction.

In addition to the circumferentially-distributed waistband zones havingdiffering coefficients of static friction, the diaper can also havevarying coefficient of static friction zones that are outside the innerwaistband area. For example, and referring to FIG. 2, zones that vary incoefficient of friction can also be provided on the skin-facing surfacesof areas such as central panels 8 and 9 and ear panels 10 and 11 thatextend between waistband 6, 7 and crotch region 30.

Referring to FIG. 25, diaper 20c includes high coefficient of staticfriction hip-contacting zones 550 on each side of the diaper along theinner surfaces of waistband 37, and intermediate coefficient of staticfriction zones 560 on each side of high coefficient of static frictionzones 550. Intermediate coefficient of static friction zones 560 extendfrom waistband 37 to leg edges 153 and 156. In that regard, theinterior, body-contacting surfaces of panels 46 and 48 that define thoseintermediate coefficient of static friction areas can each be providedwith an interior coating or a separately-applied material that providesan intermediate level of coefficient of static friction value of fromabout 0.2 to about 1.5. And the front and rear panels defined by theinterior surface of topsheet 24 can include a low coefficient of staticfriction material, having a coefficient of static friction of from about0.05 to about 0.20, because those areas undergo greater degrees ofmovement relative to the skin of the wearer as the wearer moves about,thereby contributing to greater wearer comfort and reduced skinirritation in those areas experiencing greater relative movement betweenthe skin and the interior surface of the diaper.

The invention has been described herein principally in the context of apre-assembled, pull-on diaper that is in ready-to-wear condition asreceived and that does not require attachment of particular structuralelement to each other by the person who applies the diaper to the bodyof a wearer. An example of such a pull-on diaper is the structuredisclosed in U.S. Pat. No. 5,685,874, entitled “Disposable Pull-OnPant,” which issued to Kenneth B. Buell et al., on Nov. 11, 1997.

Another form of diaper structure in which the present invention can beadvantageously employed is the relatively flat diaper structure that isapplied to the body of a wearer and that requires the person who appliesthe diaper to connect fastener elements to retain the diaper in wearingposition on the body of the wearer, such as by the manipulation andattachment of tape-type fasteners. One such non-assembled diaperstructure, one that is in substantially flat condition as received, isdisclosed in U.S. Pat. No. 5,151,092, entitled “Absorbent Article withDynamic Elastic Waist Feature Having a Predisposed Resilient FlexuralHinge,” which issued to Kenneth B. Buell et al., on Sep. 29, 1992. Thedisclosures of each of the foregoing Buell et al. patents are herebyincorporated herein by reference to the same extent as if fullyrewritten.

Although described hereinabove in the context of a pre-formed, pull-ondiaper, the present invention involving the provision of selectivelydifferent areas of coefficient of static friction can also be utilizedin other absorbent articles that are worn. In addition to the pull-ondiaper and the flat diaper structures, the present invention can also beemployed in disposable absorbent articles commonly referred to as“convertible diapers,” or “convertible belted diapers.” Such so-calledconvertible structures include a fastening system that providesdifferent assembly and application and removal alternatives. Thosealternatives allow the convertible structure to be used either in apre-assembled, pull-on form, or in a non-pre-assembled, flat form, toenable the person applying and removing the diaper to select how thearticle is applied to and removed from the body of the wearer. Forexample, the convertible diaper can be applied and removed by pullingthe diaper up or down along the legs of the wearer, or it can be appliedby wrapping the diaper about the torso of the wearer and utilizing thefastening system to retain it in wearing position, and can be removed byreleasing the fastening system and opening the diaper for removal fromthe wearer. The convertible diaper structures therefore include afastening system that permits a choice between a pre-assembled, pull-ondiaper, and a conventional, flat, non-pre-assembled diaper. Thefastening system facilitates easy application and removal of the diaper,as well as easy opening of the diaper while it is worn, for inspectionfor soiling. One form of such a convertible diaper structure isdisclosed in U.S. Statutory Invention Registration No. H1674, entitled“Convertible Belted Diaper,” which names as inventors Kathleen Q. Ameset al., and which was published on Aug. 5, 1997, the disclosure of whichis hereby incorporated herein by reference to the same extent as iffully rewritten.

Although particular embodiments of the present invention have beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications can be made without departingfrom the spirit of the present invention. It is therefore intended toencompass within the appended claims all such changes and modificationsthat fall within the scope of the present invention.

What is claimed is:
 1. A disposable garment adapted to be worn on thelower torso of a wearer, said garment comprising: a. a chassis includinga topsheet, a backsheet joined with the topsheet, and an absorbent coreinterposed between the topsheet and the backsheet, the chassis having afront region, a back region, and a crotch region positioned between thefront region and the back region, the chassis including side edges andend edges and having body-facing surfaces and surfaces that face awayfrom the body of a wearer; b. a pair of side seams joining portions ofthe side edges of the chassis at the front region to other portions ofthe respective side edges of the chassis at the back region to define apair of side panels adapted to overlie a hip area of a wearer and toform a garment having a pair of laterally spaced leg openings and awaistband defining a waist opening spaced from each of the leg openingsand including a body-facing waistband inner surface, wherein thewaistband and the side panels are elastically extensible; and c. atleast one garment retention zone positioned interiorly of the garment atthe waist opening, the garment retention zone having a surface slipresistance of at least about 1000 gm and having a coefficient of staticfriction that is at least about 200% greater than that of otherbody-contacting portions of the waistband, to assist in retention of thegarment in a desired wearing position on the body of a wearer.
 2. Adisposable garment in accordance with claim 1 wherein the area of theretention zone is from about 0.25 in² to about 10 in².
 3. A disposablegarment in accordance with claim 1 wherein the coefficient of staticfriction in the retention zone is from about 0.5 to about 3.0.
 4. Adisposable garment in accordance with claim 1 wherein the garmentincludes plural retention zones.
 5. A disposable garment in accordancewith claim 4 wherein retention zones are positioned at areas of thegarment that contact the hip areas of a wearer when the garment is worn.6. A disposable garment in accordance with claim 4 wherein the garmentincludes a retention zone at a back-contacting area of the waistband ofthe garment.
 7. A disposable garment in accordance with claim 1 whereinthe retention zone is air permeable.
 8. A disposable garment inaccordance with claim 1 wherein the retention zone is a continuous areaand has a substantially uniform coefficient of static friction over itsarea.
 9. A disposable garment in accordance with claim 1 including aplurality of first retention zones each having a first coefficient ofstatic friction, and intervening second retention zones between thefirst retention zones, the intervening retention zones having a secondcoefficient of static friction different from that of the firstretention zones.
 10. A disposable garment in accordance with claim 9wherein the second coefficient of static friction is lower than thefirst coefficient of static friction.
 11. A disposable garment inaccordance with claim 1 wherein the retention zone is defined by acoating that overlies a portion of an interior, body-facing surface ofthe waistband.
 12. A disposable garment in accordance with claim 11wherein the coating is selected from the group consisting of polymericmaterials, pressure-sensitive adhesive materials, rubber-basedmaterials, and combinations thereof.
 13. A disposable garment inaccordance with claim 1 wherein the retention zone is defined by a thinpolymeric film that is attached to an inner surface of the waistband.14. A disposable garment in accordance with claim 1 wherein theretention zone extends along a side seam and the coefficient of staticfriction is greatest at the waistband and diminishes in value toward theleg opening.
 15. A disposable garment in accordance with claim 1including slip zones within the interior, body-facing surface of thegarment, the slip zones having a coefficient of static friction that isless than about 0.20.
 16. A disposable garment in accordance with claim15 wherein slip zones are positioned on the interior surface of thegarment adjacent the leg openings.
 17. A disposable garment inaccordance with claim 16 wherein slip zones are positioned on the innersurface of the waistband at points between the retention zones.
 18. Adisposable garment in accordance with claim 1 wherein the retention zoneis defined by a nonwoven fibrous polymeric material.
 19. A disposablegarment in accordance with claim 18 wherein the nonwoven fibrousmaterial includes meltblown polymeric fibers that are applied to aportion of the body-facing surface of the garment.
 20. A disposablegarment in accordance with claim 1 wherein the waistband includesretention zones that overlie from about 10% to about 100% of thewaistband inner circumference when the waistband is in its relaxed,unextended condition.
 21. A disposable garment in accordance with claim1 wherein the waistband includes retention zones that overlie from about25% to about 35% of the waistband inner circumference when the waistbandis in its relaxed, unextended condition.
 22. A disposable garment inaccordance with claim 1 wherein the waistband inner surface includes apivotable flap that covers the retention zone so that pivoting of theflap exposes the retention zone.
 23. A disposable garment in accordancewith claim 22 wherein the retention zone includes an elastomericmaterial forming part of the waistband of the garment and facing andunderlying the pivotable flap when the flap is in its unpivotedposition.
 24. A disposable garment in accordance with claim 22 whereinthe retention zone is carried on an inner surface of the pivotable flap.25. A disposable garment in accordance with claim 22 wherein the flapincludes a first, body-facing surface having a first coefficient ofstatic friction and a second surface that initially faces away from thebody of the wearer and that has a second coefficient of static frictiondifferent from that of the first surface.
 26. A disposable garment inaccordance with claim 25 wherein the first coefficient of staticfriction is less than the second coefficient of static friction.
 27. Adisposable garment in accordance with claim 26 wherein the firstcoefficient of static friction is less than about 0.2 and the secondcoefficient of static friction is at least about 0.5.
 28. A disposablegarment in accordance with claim 1 wherein the retention zone has asurface slip resistance of at least about 2100 gm.
 29. A disposablegarment in accordance with claim 1 wherein the retention zone has asurface slip resistance of at least about 1500 gm.
 30. A disposablegarment in accordance with claim 1 wherein the retention zone has anouter, skin-facing surface defined by an elastomeric material.
 31. Adisposable garment in accordance with claim 30 wherein the elastomericmaterial has a coefficient of static friction of about 3.0.
 32. Adisposable garment in accordance with claim 1 wherein the waistbandincludes: a. an extensible outer layer of nonwoven material that has asoft, cloth-like feel and appearance; b. an extensible inner layer ofnonwoven material that has a soft, cloth-like feel and appearance; c. anextensible intermediate layer including a material having a highercoefficient of static friction than the inner layer positioned betweeneach of the inner and outer nonwoven layers to define the waistband,wherein the intermediate layer is bonded to at least portions of theinner layer to provide bonded areas and unbonded areas, wherein thehigher coefficient of static friction material is elastically extensiblein a circumferential direction of the waistband; and d. a plurality ofspaced cuts extending through the inner layer from a lower edge thereofto a point between the lower edge and an upper edge thereof to define atleast one circumferential flap member, the flap member overlying anunbonded area between the inner layer and the intermediate layer so thatthe flap member is pivotable about a circumferential pivot lineinterconnecting a pair of consecutive spaced cuts to expose the highercoefficient of static friction material when the waistband structure ismoved over the skin of the user in a direction that is substantiallyparallel to an inner surface of the inner layer and substantiallyperpendicular to a circumferential stretch direction of the waistband.33. A disposable garment in accordance with claim 17, includingintermediate coefficient of static friction zones positioned between theretention zones and the slip zones.
 34. A disposable garment inaccordance with claim 33 wherein the intermediate coefficient of staticfriction zones have a coefficient of static friction of from about 0.20to about 1.5.
 35. A disposable garment in accordance with claim 34wherein the retention zones have a coefficient of static friction offrom about 0.5 to about 3.0.
 36. A disposable garment in accordance withclaim 1 wherein the garment includes ear panels that extend between thewaistband and the leg openings, the ear panels having inner, skin-facingsurfaces that have a coefficient of static friction that varies fromabout 1.5 to about 3.0 adjacent the waistband to from about 0.05 toabout 0.20 adjacent the leg openings.
 37. A disposable garment inaccordance with claim 1 wherein the waistband includes: a. an extensibleouter layer of nonwoven material that has a soft, cloth-like feel andappearance; b. an extensible inner layer of nonwoven material that has asoft, cloth-like feel and appearance; and c. an extensible intermediatelayer including a material having a higher coefficient of staticfriction than the inner layer positioned between each of the inner andouter nonwoven layers to define the waistband, wherein the intermediatelayer is bonded to at least portions of the inner layer to providebonded areas and unbonded areas, wherein the higher coefficient ofstatic friction material is elastically extensible in a circumferentialdirection of the waistband; d. the extensible inner layer including aplurality of pivotable, circumferentially extending flaps overlyingrespective unbonded areas, wherein the flaps are pivotable aboutrespective pivot axes that extend in a circumferential directionrelative to the waistband to expose the higher coefficient of staticfriction material.
 38. A disposable garment in accordance with claim 32wherein the higher coefficient of static friction material is anelastomeric scrim.
 39. A disposable garment in accordance with claim 1wherein the waistband includes: a. an extensible outer layer of nonwovenmaterial that has a soft, cloth-like feel and appearance; b. anextensible inner layer of nonwoven material that has a soft, cloth-likefeel and appearance; and c. an extensible intermediate layer including amaterial having a higher coefficient of static friction than the innerlayer positioned between each of the inner and outer nonwoven layers todefine the waistband, wherein the intermediate layer is bonded to atleast portions of the inner layer to provide bonded areas and unbondedareas, wherein the higher coefficient of static friction material iselastically extensible in a circumferential direction of the waistband;d. wherein the inner layer includes a plurality of spaced slitsextending through the inner layer and extending transversely relative toa circumferential dimension of the waistband, so that uponcircumferential extension of the waistband the slits open to expose thehigher coefficient of static friction material.
 40. A disposable garmentin accordance with claim 39 wherein the higher coefficient of staticfriction material is elastomeric.
 41. A disposable garment in accordancewith claim 40 wherein the higher coefficient of static friction materialis a scrim.
 42. A disposable garment in accordance with claim 39 whereinthe slits are aligned in a plurality of side-by-side columns in whichlaterally adjacent slits are offset from each other in a longitudinaldirection of the columns.